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Sample records for 11b mas nmr

  1. (11)B MAS NMR and First-Principles Study of the [OBO3] Pyramids in Borates.

    PubMed

    Zhou, Bing; Sun, Wei; Zhao, Biao-Chun; Mi, Jin-Xiao; Laskowski, Robert; Terskikh, Victor; Zhang, Xi; Yang, Lingyun; Botis, Sanda M; Sherriff, Barbara L; Pan, Yuanming

    2016-03-07

    Borates are built from the [Bϕ3] planar triangles and the [Bϕ4] tetrahedral groups, where ϕ denotes O or OH. However, the [Bϕ4] groups in some borates are highly distorted to include three normal B-O bonds and one anomalously long B-O bond and, therefore, are best described as the [OBO3] pyramids. Four synthetic borates of the boracite-type structures (Mg3B7O13Br, Cu3B7O13Br, Zn3B7O13Cl, and Mg3B7O13Cl) containing a range of [OBO3] pyramids were investigated by multifield (7.05, 14.1, and 21.1 T) (11)B magic-angle spinning nuclear magnetic resonance (MAS NMR), triple quantum (3Q) MAS NMR experiments, as well as density functional theory calculations. The high-resolution (11)B MAS NMR spectra supported by theoretical predictions show that the [OBO3] pyramids are characterized by isotropic chemical shifts δiso((11)B) from 1.4(1) to 4.9(1) ppm and nuclear quadrupole parameters CQ((11)B) up to 1.3(1) MHz, both significantly different from those of the [BO4] and [BO3] groups in borates. These δiso((11)B) and CQ((11)B) values indicate that the [OBO3] pyramids represent an intermediate state between the [BO4] tetrahedra and [BO3] triangles and demonstrate that the (11)B NMR parameters of four-coordinate boron oxyanions are sensitive to local structural environments. The orientation of the calculated unique electronic field gradient tensor element Vzz of the [OBO3] pyramids is aligned approximately along the direction of the anomalously long B-O bond, corresponding to B-2pz with the lowest electron density.

  2. Red coralline algae assessed as marine pH proxies using 11B MAS NMR

    NASA Astrophysics Data System (ADS)

    Cusack, M.; Kamenos, N. A.; Rollion-Bard, C.; Tricot, G.

    2015-02-01

    Reconstructing pH from biogenic carbonates using boron isotopic compositions relies on the assumption that only borate, and no boric acid, is present. Red coralline algae are frequently used in palaeoenvironmental reconstruction due to their widespread distribution and regular banding frequency. Prior to undertaking pH reconstructions using red coralline algae we tested the boron composition of the red coralline alga Lithothamnion glaciale using high field NMR. In bulk analysed samples, thirty percent of boron was present as boric acid. We suggest that prior to reconstructing pH using coralline algae 1) species-specific boron compositions and 2) within-skeleton special distributions of boron are determined for multiple species. This will enable site selective boron analyses to be conducted validating coralline algae as palaeo-pH proxies based on boron isotopic compositions.

  3. (Na{sub 4}BH{sub 4}){sup 3+} guests inside aluminosilicate, gallosilicate and aluminogermanate sodalite host frameworks studied by {sup 1}H, {sup 11}B, and {sup 23}Na MAS NMR spectroscopy

    SciTech Connect

    Buhl, J.-Ch.; Murshed, M.M.

    2009-07-01

    We report tetrahydroborate aluminosilicate, gallosilicate and aluminogermanate sodalites studied by {sup 11}B, {sup 1}H and {sup 23}Na MAS NMR spectroscopy. The spectral parameters are consistent with the local environments of each investigated nucleus obtained from the crystal structures. The {sup 11}B MAS NMR spectra exhibit a sharp narrow line at about -49.0 ppm, which is assigned to BH{sub 4}{sup -} enclathrated into the sodalite framework matrix. The lineshape of the signal shows no quadrupolar interactions due to discreteness and high symmetry of the BH{sub 4}{sup -} unit as well as possible fast dynamic site exchange of hydrogen atoms. The {sup 23}Na MAS NMR signals also show a narrow Gaussian lineshape, which clearly indicates a single type of sodium coordination, and a centrosymmetrical charge distribution around the sodium atom. The {sup 1}H MAS NMR spectra can clearly distinguish between hydrogen in BH{sub 4}{sup -} anions (-0.6 ppm), H{sub 3}O{sub 2}{sup -} anions (1.2 ppm) and H{sub 2}O molecules (5.0 ppm). The structural properties of BH{sub 4}{sup -} intercalation into sodalite framework matrix help connect the microporous materials to hydride-containing A, X and Y type zeolites.

  4. MAS NMR of HIV-1 protein assemblies

    NASA Astrophysics Data System (ADS)

    Suiter, Christopher L.; Quinn, Caitlin M.; Lu, Manman; Hou, Guangjin; Zhang, Huilan; Polenova, Tatyana

    2015-04-01

    The negative global impact of the AIDS pandemic is well known. In this perspective article, the utility of magic angle spinning (MAS) NMR spectroscopy to answer pressing questions related to the structure and dynamics of HIV-1 protein assemblies is examined. In recent years, MAS NMR has undergone major technological developments enabling studies of large viral assemblies. We discuss some of these evolving methods and technologies and provide a perspective on the current state of MAS NMR as applied to the investigations into structure and dynamics of HIV-1 assemblies of CA capsid protein and of Gag maturation intermediates.

  5. High resolution 11B NMR of MgB2 using cryogenic magic-angle spinning

    NASA Astrophysics Data System (ADS)

    Stern, Raivo; Beckett, Peter; Denning, Mark S.; Heinmaa, Ivo; Dimri, Mukesh C.; Young, Edward A.; Carravetta, Marina

    2013-03-01

    Static and magic-angle spinning (MAS) 11B NMR data at 4.7 T and 8.5 T have been obtained under cryogenic conditions on a diluted sample of magnesium diboride powder in the normal and superconducting state. We demonstrate that MAS NMR is possible on type-II superconductors despite the sample rotation. The data provide accurate information on the magnetic shift variation and longitudinal relaxation data down to a temperature of 8 K, with a resolution improvement over the entire temperature range. The onset of superconductivity is unaffected by the sample rotation, as revealed by a steep variation of the magnetic shift just below the critical temperature. Appeared in JCP 137, 114201, http://dx.doi.org/10.1063/1.4751476

  6. Structural biology applications of solid state MAS DNP NMR.

    PubMed

    Akbey, Ümit; Oschkinat, Hartmut

    2016-08-01

    Dynamic Nuclear Polarization (DNP) has long been an aim for increasing sensitivity of nuclear magnetic resonance (NMR) spectroscopy, delivering spectra in shorter experiment times or of smaller sample amounts. In recent years, it has been applied in magic angle spinning (MAS) solid-state NMR to a large range of samples, including biological macromolecules and functional materials. New research directions in structural biology can be envisaged by DNP, facilitating investigations on very large complexes or very heterogeneous samples. Here we present a summary of state of the art DNP MAS NMR spectroscopy and its applications to structural biology, discussing the technical challenges and factors affecting DNP performance.

  7. Structural biology applications of solid state MAS DNP NMR

    NASA Astrophysics Data System (ADS)

    Akbey, Ümit; Oschkinat, Hartmut

    2016-08-01

    Dynamic Nuclear Polarization (DNP) has long been an aim for increasing sensitivity of nuclear magnetic resonance (NMR) spectroscopy, delivering spectra in shorter experiment times or of smaller sample amounts. In recent years, it has been applied in magic angle spinning (MAS) solid-state NMR to a large range of samples, including biological macromolecules and functional materials. New research directions in structural biology can be envisaged by DNP, facilitating investigations on very large complexes or very heterogeneous samples. Here we present a summary of state of the art DNP MAS NMR spectroscopy and its applications to structural biology, discussing the technical challenges and factors affecting DNP performance.

  8. High resolution 11B NMR of magnesium diboride using cryogenic magic angle spinning

    NASA Astrophysics Data System (ADS)

    Beckett, Peter; Denning, Mark S.; Heinmaa, Ivo; Dimri, Mukesh C.; Young, Edward A.; Stern, Raivo; Carravetta, Marina

    2012-09-01

    Static and magic-angle spinning 11B nuclear magnetic resonance (NMR) data at 4.7 T and 8.5 T have been obtained under cryogenic conditions on a diluted sample of magnesium diboride powder in the normal and superconducting state. The data provide accurate information on the magnetic shift and longitudinal relaxation time down to a temperature of 8 K, with a resolution improvement over the entire temperature range. The onset of superconductivity is unaffected by the sample rotation, as revealed by a steep variation of the magnetic shift just below the critical temperature.

  9. Boric Acid Adsorption onto Humic Acids: Structures, Stabilities, 11B NMR and 11B,10B Isotopic Fractionations of Surface Complexes

    NASA Astrophysics Data System (ADS)

    Tossell, J. A.

    2006-05-01

    Boric acid, B(OH)3, forms complexes in aqueous solution with a number of bidentate O-containing ligands, L- 2, such as C2O4-2 (oxalate), C3H2O4-2 (malonate), C2H4O2-2 (glycolate), C6H4O2-2 (catecholate) and C10H6O2-2 (dioxynaphthalene). McElligot and Byrne (1998) have also found it to form a complex with CO3-2. Recently Lemarchand, et al. (2005) have studied the formation of surface complexes of B(OH)3 on humic acid, determining formation constants, 11B NMR shifts and 11B,10B isotope fractionations for a number of such complexes. This helps to clarify both the interaction of boric acid with the humic acid and the nature of the coordinating sites on the humic acid. The determination of isotope fractionations may be seen as a form of vibrational spectroscopy, using the fractionating element as a local probe of the vibrational spectrum which determines the fractionation. We have calculated quantum mechanically the structures, stabilities, vibrational spectra, 11B NMR spectra and 11B,110B isotope fractionations of a number of complexes B(OH)2L- formed by reactions of the type: B(OH)3 + HL- ? B(OH)2L- + H2O (1) using the 6-311G(d,p) B3LYP method for structures and isotopic fractionations, the highly accurate Complete Basis Set-QB3 method for energetics and the GIAO HF method with a 6-311+G(2d,p) basis for the NMR shieldings. Oxalic acid, malonic acid and catechol all form stable complexes (?G<0 for reaction 1),which are deshielded (less negative ?) vs. B(OH)4- by 2.7, 0.6 and 5.6 ppm, respectively, and which are isotopically lighter than B(OH)4- (more negative ? 11B) by 3, 2 and 5 ‰, respectively. The calculated 11B NMR shifts match well with the results of Lemarchand, et al. (2005) while the calculated isotopic fractionations are qualitatively consistent with their results, but show much smaller deviations from B(OH)4-. This is probably a consequence of the use by these authors of a value of 1.0194 (Kakihana, et al., 1977) for the 11B,10B isotopic exchange

  10. Spatially resolved solid-state MAS-NMR-spectroscopy.

    PubMed

    Scheler, U; Schauss, G; Blümich, B; Spiess, H W

    1996-07-01

    A comprehensive account of spatially resolved solid-state MAS NMR of 13C is given. A device generating field gradients rotating synchronously with the magic angle spinner is described. Spatial resolution and sensitivity are compared for phase and frequency encoding of spatial information. The suppression of spinning sidebands is demonstrated for both cases. Prior knowledge about the involved materials can be used for the reduction of data from spatially resolved spectra to map chemical structure. Indirect detection via 13C NMR gives access to the information about mobility from proton-wideline spectra. Two-dimensional solid-state spectroscopy with spatial resolution is demonstrated for a rotor synchronized MAS experiment which resolves molecular order as a function of space. By comparison of different experiments the factors affecting the spatial resolution are investigated.

  11. Boric acid adsorption on humic acids: Ab initio calculation of structures, stabilities, 11B NMR and 11B, 10B isotopic fractionations of surface complexes

    NASA Astrophysics Data System (ADS)

    Tossell, J. A.

    2006-10-01

    Boric acid, B(OH) 3, forms complexes in aqueous solution with a number of bidentate O-containing ligands, HL -, where H 2L is C 2O 4H 2 (oxalic acid), C 3O 4H 4 (malonic acid), C 2H 6O 2 (ethylene glycol), C 6H 6O 2 (catechol), C 10H 8O 2 (dioxynaphthalene) and C 2O 3H 4 (glycolic acid). McElligott and Byrne [McElligott, S., Byrne, R.H., 1998. Interaction of B(OH)30 and HCO3- in seawater: Formation of B(OH)CO3-. Aquat. Geochem.3, 345-356.] have also found B(OH) 3 to form an aqueous complex with HCO3-1. Recently Lemarchand et al. [Lemarchand, E., Schott, J., Gaillardeet, J., 2005. Boron isotopic fractionation related to boron sorption on humic acid and the structure of surface complexes formed. Geochim. Cosmochim. Acta69, 3519-3533] have studied the formation of surface complexes of B(OH) 3 on humic acid, determining 11B NMR shifts and fitted values of formation constants, and 11B, 10B isotope fractionations for a number of surface complexation models. Their work helps to clarify both the nature of the interaction of boric acid with the functional groups in humic acid and the nature of some of these coordinating sites on the humic acid. The determination of isotope fractionations may be seen as a form of vibrational spectroscopy, using the fractionating element as a local probe of the vibrational spectrum. We have calculated quantum mechanically the structures, stabilities, vibrational spectra, 11B NMR spectra and 11B, 10B isotope fractionations of a number of complexes B(OH) 2L - formed by reactions of the type: B(OH)3+HL-⇒B(OH)2L+HO using a 6-311G(d,p) basis set and the B3LYP method for determination of structures, vibrational frequencies and isotopic fractionations, the highly accurate Complete Basis Set-QB3 method for calculating the free energies and the GIAO HF method with a 6-311+G(2d,p) basis for the NMR shieldings. The calculations indicate that oxalic acid, malonic acid, catechol and glycolic acid all form stable complexes (Δ G < 0 for Reaction (1

  12. A General Protocol for Temperature Calibration of MAS NMR Probes at Arbitrary Spinning Speeds

    PubMed Central

    Guan, Xudong; Stark, Ruth E.

    2010-01-01

    A protocol using 207Pb NMR of solid lead nitrate was developed to determine the temperature of magic-angle spinning (MAS) NMR probes over a range of nominal set temperatures and spinning speeds. Using BioMAS and fastMAS probes with typical sample spinning rates of 8 and 35 kHz, respectively, empirical equations were devised to predict the respective sample temperatures. These procedures provide a straightforward recipe for temperature calibration of any MAS probe. PMID:21036557

  13. Strong-coupling s-wave Superconductor MgB2 : ^11B NMR Study

    NASA Astrophysics Data System (ADS)

    Kotegawa, Hisashi; Ishida, Kenji; Kitaoka, Yoshio; Muranaka, Takahiro; Nakagawa, Norimasa; Takagiwa, Hiroyuki; Akimitsu, Jun

    2002-03-01

    We report nuclear magnetic resonance (NMR) results on the recently discovered superconductor MgB_2. This binary compound exhibits a remarkably high superconducting (SC) transition temperature, Tc of ~40K, and thus attracts a great deal of attention. Numerous theoretical and experimental approaches have been performed in order to investigate SC characteristics in this compound. We have investigated a SC gap structure of MgB2 through the measurement of ^11B nuclear spin-lattice relaxation time, T_1. ^11(1/T_1T) is independent of the temperature (T) in the normal state, and decreases exponentially in the SC state, accompanied with a tiny coherence peak just below T_c. The T dependence of 1/T_1T in the SC state can be accounted for by an s-wave SC model with a large gap size of 2Δ /k_BTc ~ 5 which suggests to be in a strong-coupling regime. We carried out the measurement in Al-doped Mg_1-xAl_xB_2. 1/T1 in the SC state revealed that the size in SC gap is not changed by substituting Al for Mg. The reduction in Tc is shown to be due to the decrease of N(E_F). According to the McMillan equation, the experimental relation between Tc and the relative change in N(E_F) allowed us to estimate a characteristic phonon frequency ω ~ 700K and an electron-phonon coupling constant λ ~ 0.87. These results suggest that the high-Tc superconductivity in MgB2 is mediated by the strong electron-phonon coupling with high-frequency phonons.

  14. Effect of pressure on the intermediate-valence semiconductor SmB6: 11B-NMR

    NASA Astrophysics Data System (ADS)

    Nishiyama, Kohei; Mito, Takeshi; Ueda, Ko-ichi; Koyama, Takehide; Kohara, Takao; Pristáš, Gabriel; Gabáni, Slavomír; Reiffers, Marián; Flachbart, Karol; Komaki, Yasuhiro; Kokubu, Mitsutane; Fukazawa, Hideto; Kohori, Yoh; Takeshita, Nao; Shitsevalova, Natalia

    2013-06-01

    We report the first high-pressure 11B-NMR studies above 3 GPa on the intermediate-valence semiconductor SmB6. A 11B-NMR line obtained at 4.9 GPa, the highest pressure for the measurements, and at 1.9 K shows quite similar a line shape to that at ambient pressure, indicating no structural or magnetic phase transition up to this pressure. The temperature dependence of the spin lattice relaxation rate 1/ T 1 at 4.9 GPa still exhibits an activation-type temperature dependence characteristic of semiconductors, which reveals an obvious decrease in the insulating gap by about 30% compared to the gap at ambient pressure. The present experimental facts of a finite insulator gap and no magnetic order at 4.9 GPa are consistent with recent transport measurements performed under better hydrostatic pressures.

  15. MAS-NMR investigations of the crystallization behaviour of lithium aluminum silicate (LAS) glasses containing P 2O 5 and TiO 2 nucleants

    NASA Astrophysics Data System (ADS)

    Ananthanarayanan, A.; Kothiyal, G. P.; Montagne, L.; Revel, B.

    2010-06-01

    Lithium aluminum silicate (LAS) glass of composition (mol%) 20.4Li 2O-4.0Al 2O 3-68.6SiO 2-3.0K 2O-2.6B 2O 3-0.5P 2O 5-0.9TiO 2 was prepared by melt quenching. The glass was then nucleated and crystallized based on differential thermal analysis (DTA) data and was characterized by 29Si, 31P, 11B and 27Al MAS-NMR. XRD and 29Si NMR showed that lithium metasilicate (Li 2SiO 3) is the first phase to c form followed by cristobalite (SiO 2) and lithium disilicate (Li 2Si 2O 5). 29Si MAS-NMR revealed a change in the network structure already for the glasses nucleated at 550 °C. Since crystalline Li 3PO 4, as observed by 31P MAS-NMR, forms concurrently with the silicate phases, we conclude that crystalline Li 3PO 4 does not act as a nucleating agent for lithium silicate phases. Moreover, 31P NMR indicates the formation of M-PO 4 ( M=B, Al or Ti) complexes. The presence of BO 3 and BO 4 structural units in all the glass/glass-ceramic samples is revealed through 11B MAS-NMR. B remains in the residual glass and the crystallization of silicate phases causes a reduction in the number of alkali ions available for charge compensation. As a result, the number of trigonally coordinated B (BO 3) increases at the expense of tetrahedrally coordinated B (BO 4). The 27Al MAS-NMR spectra indicate the presence of tetrahedrally coordinated Al species, which are only slightly perturbed by the crystallization.

  16. (11)B Solid-State NMR Interaction Tensors of Linear Two-Coordinate Boron: The Dimesitylborinium Cation.

    PubMed

    Alain, Amanda E; Shoji, Yoshiaki; Fukushima, Takanori; Bryce, David L

    2015-12-21

    Borinium cations (R2B(+)) are of particular fundamental and applied interest in part due to their pronounced Lewis acidity which enables unique chemical transformations. Solid-state NMR spectroscopy of magic-angle spinning and stationary powdered samples of the dicoordinate boron cation in the recently reported dimesitylborinium tetrakis(pentafluorophenyl)borate compound (Shoji et al. Nature Chem. 2014, 6, 498) is applied to characterize the (11)B electric field gradient (EFG) and chemical shift (CS) tensors. The experimental data are consistent with linear C-B(+)-C geometry. The (11)B quadrupolar coupling constant, 5.44 ± 0.08 MHz, and the span of the CS tensor, 130 ± 1 ppm, are both particularly large relative to literature data for a variety of boron functional groups, and represent the first such data for the linear C-B(+)-C borinium moiety. The NMR data are similar to those for the neutral tricoordinate analogue, trimesitylborane, but contrast with those of the Cp*2B(+) cation. Quantum chemical calculations are applied to provide additional insights into the relationship between the NMR observables and the molecular and electronic structure of the dimesitylborinium cation.

  17. Sealed rotors for in situ high temperature high pressure MAS NMR

    DOE PAGES

    Hu, Jian Z.; Hu, Mary Y.; Zhao, Zhenchao; ...

    2015-07-06

    Magic angle spinning (MAS) nuclear magnetic resonance (NMR) investigations on heterogeneous samples containing solids, semi-solids, liquid and gases or a mixture of them under non-conventional conditions of a combined high pressure and high temperature, or cold temperature suffer from the unavailability of a perfectly sealed rotor. Here, we report the design of reusable and perfectly-sealed all-zircornia MAS rotors. The rotors are easy to use and are suitable for operation temperatures from below 0 to 250 °C and pressures up to 100 bar. As an example of potential applications we performed in situ MAS NMR investigations of AlPO₄-5 molecular sieve crystallization,more » a kinetic study of the cyclohexanol dehydration reaction using 13C MAS NMR, and an investigation of the metabolomics of intact biological tissue at low temperature using 1H HR-MAS NMR spectroscopy. The in situ MAS NMR experiments performed using the reported rotors allowed reproduction of the results from traditional batch reactions, while offering more detailed quantitative information at the molecular level, as demonstrated for the molecular sieve synthesis and activation energy measurements for cyclohexanol dehydration. The perfectly sealed rotor also shows promising application for metabolomics studies using 1H HR-MAS NMR.« less

  18. Sealed rotors for in situ high temperature high pressure MAS NMR

    SciTech Connect

    Hu, Jian Z.; Hu, Mary Y.; Zhao, Zhenchao; Xu, Souchang; Vjunov, Aleksei; Shi, Hui; Camaioni, Donald M.; Peden, Charles H. F.; Lercher, Johannes A.

    2015-07-06

    Magic angle spinning (MAS) nuclear magnetic resonance (NMR) investigations on heterogeneous samples containing solids, semi-solids, liquid and gases or a mixture of them under non-conventional conditions of a combined high pressure and high temperature, or cold temperature suffer from the unavailability of a perfectly sealed rotor. Here, we report the design of reusable and perfectly-sealed all-zircornia MAS rotors. The rotors are easy to use and are suitable for operation temperatures from below 0 to 250 °C and pressures up to 100 bar. As an example of potential applications we performed in situ MAS NMR investigations of AlPO₄-5 molecular sieve crystallization, a kinetic study of the cyclohexanol dehydration reaction using 13C MAS NMR, and an investigation of the metabolomics of intact biological tissue at low temperature using 1H HR-MAS NMR spectroscopy. The in situ MAS NMR experiments performed using the reported rotors allowed reproduction of the results from traditional batch reactions, while offering more detailed quantitative information at the molecular level, as demonstrated for the molecular sieve synthesis and activation energy measurements for cyclohexanol dehydration. The perfectly sealed rotor also shows promising application for metabolomics studies using 1H HR-MAS NMR.

  19. Structural investigations of borosilicate glasses containing MoO 3 by MAS NMR and Raman spectroscopies

    NASA Astrophysics Data System (ADS)

    Caurant, D.; Majérus, O.; Fadel, E.; Quintas, A.; Gervais, C.; Charpentier, T.; Neuville, D.

    2010-01-01

    High molybdenum concentration in glass compositions may lead to alkali and alkaline-earth molybdates crystallization during melt cooling that must be controlled particularly during the preparation of highly radioactive nuclear glassy waste forms. To understand the effect of molybdenum addition on the structure of a simplified nuclear glass and to know how composition changes can affect molybdates crystallization tendency, the structure of two glass series belonging to the SiO 2-B 2O 3-Na 2O-CaO-MoO 3 system was studied by 29Si, 11B, 23Na MAS NMR and Raman spectroscopies by increasing MoO 3 or B 2O 3 concentrations. Increasing MoO 3 amount induced an increase of the silicate network reticulation but no significant effect was observed on the proportion of BO4- units and on the distribution of Na + cations in glass structure. By increasing B 2O 3 concentration, a strong evolution of the distribution of Na + cations was observed that could explain the evolution of the nature of molybdate crystals (CaMoO 4 or Na 2MoO 4) formed during melt cooling.

  20. Ammonia Vapor Removal by Cu3(BTC)2 and Its Characterization by MAS NMR

    DTIC Science & Technology

    2009-01-01

    further confirmation of these assignments, Soxhlet - extracted (MeOH) Cu3(BTC)2 is totally devoid of both DMF peaks, leaving only the pristine methine...samples, 1H and 13C MAS NMR spectra for solvent extracted Cu3(BTC)2 and (NH4)3BTC, Figure 15. 1H MAS NMR spectra obtained for Cu3(BTC)2 exposed to NH3

  1. Investigation of domain size in polymer membranes using double quantum filtered spin diffusion MAS NMR.

    SciTech Connect

    Fujimoto, Cy H.; Alam, Todd Michael; Cherry, Brian Ray; Cornelius, Christopher James

    2005-02-01

    Solid-state {sup 1}H magic angle spinning (MAS) NMR was used to investigate sulfonated Diels-Alder poly(phenlylene) polymer membranes. Under high spinning speed {sup 1}H MAS conditions, the proton environments of the sulfonic acid and phenylene polymer backbone are resolved. A double-quantum (DQ) filter using the rotor-synchronized back-to-back (BABA) NMR multiple-pulse sequence allowed the selective suppression of the sulfonic proton environment in the {sup 1}H MAS NMR spectra. This DQ filter in conjunction with a spin diffusion NMR experiment was then used to measure the domain size of the sulfonic acid component within the membrane. In addition, the temperature dependence of the sulfonic acid spin-spin relaxation time (T{sub 2}) was determined, providing an estimate of the activation energy for the proton dynamics of the dehydrated membrane.

  2. Factor analysis of 27Al MAS NMR spectra for identifying nanocrystalline phases in amorphous geopolymers.

    PubMed

    Urbanova, Martina; Kobera, Libor; Brus, Jiri

    2013-11-01

    Nanostructured materials offer enhanced physicochemical properties because of the large interfacial area. Typically, geopolymers with specifically synthesized nanosized zeolites are a promising material for the sorption of pollutants. The structural characterization of these aluminosilicates, however, continues to be a challenge. To circumvent complications resulting from the amorphous character of the aluminosilicate matrix and from the low concentrations of nanosized crystallites, we have proposed a procedure based on factor analysis of (27)Al MAS NMR spectra. The capability of the proposed method was tested on geopolymers that exhibited various tendencies to crystallize (i) completely amorphous systems, (ii) X-ray amorphous systems with nanocrystalline phases, and (iii) highly crystalline systems. Although the recorded (27)Al MAS NMR spectra did not show visible differences between the amorphous systems (i) and the geopolymers with the nanocrystalline phase (ii), the applied factor analysis unambiguously distinguished these materials. The samples were separated into the well-defined clusters, and the systems with the evolving crystalline phase were identified even before any crystalline fraction was detected by X-ray powder diffraction. Reliability of the proposed procedure was verified by comparing it with (29)Si MAS NMR spectra. Factor analysis of (27)Al MAS NMR spectra thus has the ability to reveal spectroscopic features corresponding to the nanocrystalline phases. Because the measurement time of (27)Al MAS NMR spectra is significantly shorter than that of (29)Si MAS NMR data, the proposed procedure is particularly suitable for the analysis of large sets of specifically synthesized geopolymers in which the formation of the limited fractions of nanocrystalline phases is desired.

  3. Pulsed field gradient multiple-quantum MAS NMR spectroscopy of half-integer spin quadrupolar nuclei

    NASA Astrophysics Data System (ADS)

    Fyfe, C. A.; Skibsted, J.; Grondey, H.; Meyer zu Altenschildesche, H.

    1997-12-01

    Pulsed field gradients (PFGs) have been applied to select coherence transfer pathways in multiple-quantum (MQ) MAS NMR spectra of half-integer spin quadrupolar nuclei in rigid solids. 27Al triple-quantum (3Q) MAS NMR spectra of the aluminophosphate molecular sieves VPI-5 and AlPO 4-18 have been used to demonstrate the selection of the (0)→(3)→(-1) coherence transfer pathway using PFGs and no phase cycling. Compared to MQMAS experiments that employ phase cycling schemes, the main advantage of the PFG-MQMAS technique is its simplicity, which should facilitate the combination of MQMAS with other pulse sequences.

  4. Advanced instrumentation for DNP-enhanced MAS NMR for higher magnetic fields and lower temperatures.

    PubMed

    Matsuki, Yoh; Idehara, Toshitaka; Fukazawa, Jun; Fujiwara, Toshimichi

    2016-03-01

    Sensitivity enhancement of MAS NMR using dynamic nuclear polarization (DNP) is gaining importance at moderate fields (B0<9T) and temperatures (T>90K) with potential applications in chemistry and material sciences. However, considering the ever-increasing size and complexity of the systems to be studied, it is crucial to establish DNP under higher field conditions, where the spectral resolution and the basic NMR sensitivity tend to improve. In this perspective, we overview our recent efforts on hardware developments, specifically targeted on improving DNP MAS NMR at high fields. It includes the development of gyrotrons that enable continuous frequency tuning and rapid frequency modulation for our 395 GHz-600 MHz and 460 GHz-700 MHz DNP NMR spectrometers. The latter 700 MHz system involves two gyrotrons and a quasi-optical transmission system that combines two independent sub-millimeter waves into a single dichromic wave. We also describe two cryogenic MAS NMR probe systems operating, respectively, at T ∼ 100K and ∼ 30K. The latter system utilizes a novel closed-loop helium recirculation mechanism, achieving cryogenic MAS without consuming any cryogen. These instruments altogether should promote high-field DNP toward more efficient, reliable and affordable technology. Some experimental DNP results obtained with these instruments are presented.

  5. New insights on the mechanism of palladium-catalyzed hydrolysis of sodium borohydride from 11B NMR measurements.

    PubMed

    Guella, G; Zanchetta, C; Patton, B; Miotello, A

    2006-08-31

    To gain insight on the mechanistic aspects of the palladium-catalyzed hydrolysis of NaBH(4) in alkaline media, the kinetics of the reaction has been investigated by (11)B NMR (nuclear magnetic resonance) measurements taken at different times during the reaction course. Working with BH(4)(-) concentration in the range 0.05-0.1 M and with a [substrate]/[catalyst] molar ratio of 0.03-0.11, hydrolysis has been found to follow a first-order kinetic dependence from concentration of both the substrate and the catalyst (Pd/C 10 wt %). We followed the reaction of NaBH(4) and its perdeuterated analogue NaBD(4) in H(2)O, in D(2)O and H(2)O/D(2)O mixtures. When the process was carried out in D(2)O, deuterium incorporation in BH(4)(-) afforded BH(4)(-)(n)D(n)(-) (n = 1, 2, 3, 4) species, and a competition between hydrolysis and hydrogen/deuterium exchange processes was observed. By fitting the kinetics NMR data by nonlinear least-squares regression techniques, the rate constants of the elementary steps involved in the palladium-catalyzed borohydride hydrolysis have been evaluated. Such a regression analysis was performed on a reaction scheme wherein the starting reactant BH(4)(-) is allowed both to reversibly exchange hydrogen with deuterium atoms of D(2)O and to irreversibly hydrolyze into borohydroxy species B(OD)(4)(-). In contrast to acid-catalyzed hydrolysis of sodium borohydride, our results indicate that in the palladium-catalyzed process the rate constants of the exchange processes are higher than those of the corresponding hydrolysis reactions.

  6. Optimized multiple quantum MAS lineshape simulations in solid state NMR

    NASA Astrophysics Data System (ADS)

    Brouwer, William J.; Davis, Michael C.; Mueller, Karl T.

    2009-10-01

    /Linux Operating system: UNIX/Linux Has the code been vectorised or parallelized?: Yes RAM: Example: (1597 powder angles) × (200 Samples) × (81 F2 frequency pts) × (31 F1 frequency points) = 3.5M, SMP AMD opteron Classification: 2.3 External routines: OCTAVE ( http://www.gnu.org/software/octave/), GNU Scientific Library ( http://www.gnu.org/software/gsl/), OPENMP ( http://openmp.org/wp/) Nature of problem: The optimal simulation and modeling of multiple quantum magic angle spinning NMR spectra, for general systems, especially those with mild to significant disorder. The approach outlined and implemented in C and OCTAVE also produces model parameter error estimates. Solution method: A model for each distinct chemical site is first proposed, for the individual contribution of crystallite orientations to the spectrum. This model is averaged over all powder angles [1], as well as the (stochastic) parameters; isotropic chemical shift and quadrupole coupling constant. The latter is accomplished via sampling from a bi-variate Gaussian distribution, using the Box-Muller algorithm to transform Sobol (quasi) random numbers [2]. A simulated annealing optimization is performed, and finally the non-linear jackknife [3] is applied in developing model parameter error estimates. Additional comments: The distribution contains a script, mqmasOpt.m, which runs in the OCTAVE language workspace. Running time: Example: (1597 powder angles) × (200 Samples) × (81 F2 frequency pts) × (31 F1 frequency points) = 58.35 seconds, SMP AMD opteron. References:S.K. Zaremba, Annali di Matematica Pura ed Applicata 73 (1966) 293. H. Niederreiter, Random Number Generation and Quasi-Monte Carlo Methods, SIAM, 1992. T. Fox, D. Hinkley, K. Larntz, Technometrics 22 (1980) 29.

  7. Using heat to control the sample spinning speed in MAS NMR.

    PubMed

    Mihaliuk, Eugene; Gullion, Terry

    2011-10-01

    A new approach using temperature to control the spinning speed of a sample rotor in magic-angle spinning NMR is presented. Instead of an electro-mechanical valve that regulates the flow of drive gas to control the spinning speed in traditional MAS NMR systems, we use a small heater wire located directly in the stator. The sample spinning speed is controlled very accurately with a surprisingly low heating power of 1 W. Results on a benchtop unit demonstrate the capability of the system.

  8. Multiple-quantum cross-polarization in MAS NMR of quadrupolar nuclei

    NASA Astrophysics Data System (ADS)

    Ashbrook, Sharon E.; Brown, Steven P.; Wimperis, Stephen

    1998-05-01

    Using 27Al ( I=5/2) NMR of aluminium acetylacetonate, we show that it is possible to cross-polarize from a spin I=1/2 nucleus ( 1H) directly to the central triple-quantum transition of a half-integer quadrupolar nucleus ( 27Al) in a powdered sample under MAS conditions. The optimum conditions for this multiple-quantum cross-polarization (MQCP) are investigated experimentally and compared with existing theoretical results. The new technique is applied to the recently introduced two-dimensional MQMAS experiment for recording high-resolution NMR spectra of half-integer quadrupolar nuclei.

  9. Decomposition of adsorbed VX on activated carbons studied by 31P MAS NMR.

    PubMed

    Columbus, Ishay; Waysbort, Daniel; Shmueli, Liora; Nir, Ido; Kaplan, Doron

    2006-06-15

    The fate of the persistent OP nerve agent O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate (VX) on granular activated carbons that are used for gas filtration was studied by means of 31P magic angle spinning (MAS) NMR spectroscopy. VX as vapor or liquid was adsorbed on carbon granules, and MAS NMR spectra were recorded periodically. The results show that at least 90% of the adsorbed VX decomposes within 20 days or less to the nontoxic ethyl methylphosphonic acid (EMPA) and bis(S-2-diisopropylaminoethane) {(DES)2}. Decomposition occurred irrespective of the phase from which VX was loaded, the presence of metal impregnation on the carbon surface, and the water content of the carbon. Theoretical and practical aspects of the degradation are discussed.

  10. A 29Si MAS-NMR study of transition metal site occupancy in forsterite

    NASA Astrophysics Data System (ADS)

    Mccarty, R. J.; Palke, A.; Stebbins, J. F.; Hartman, S.

    2012-12-01

    In this study, we address the problem of transition metal site occupancy in Mg-rich olivine using solid-state magic-angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy. Transition metal substitution in olivine can occur in either of the two crystallographically unique octahedral sites: the smaller, more symmetric M1 site or the larger, more distorted M2 site. Site occupancy of the transition metal is expected to correlate with ionic radius and d-orbital structure. In NMR spectroscopy the presence of paramagnetic ions, such as transition metal ions, can produce accessory peaks referred to as "contact shifts," due to the interaction between unpaired electrons on the paramagnetic ion locally associated with the resonating nucleus. The position and intensity of the contact shifts are dependent on the geometrical association such as bond distances and bond angles between the paramagnetic ion and the resonating nucleus. 29Si MAS-NMR spectra collected on synthetic forsterite (Mg2SiO4) doped with minor amounts (0.2-5%) of individual, divalent, paramagnetic, transition metal cations (Mn, Co, Ni, or Cu) substituting for Mg in the octahedral sites, reveals multiple contact shifts. An interpretation of the number of such contact shifts and their relative intensities correlated with structural information of possible 29Si-M1 and 29Si-M2 configurations, potentially allows for the assignment of specific transition metals to individual M1 or M2 sites. An analysis of the MAS-NMR data will potentially bring a new level of confidence to transition metal site occupancy in forsterite.

  11. Full differentiation and assignment of boron species in the electrolytes Li{sub 2}B{sub 6}O{sub 9}F{sub 2} and Li{sub 2}B{sub 3}O{sub 4}F{sub 3} by solid-state {sup 11}B NMR spectroscopy

    SciTech Connect

    Braeuniger, Thomas; Pilz, Thomas; Chandran, C. Vinod; Jansen, Martin

    2012-10-15

    The syntheses of two new fluorooxoborates, Li{sub 2}B{sub 3}O{sub 4}F{sub 3} and Li{sub 2}B{sub 6}O{sub 9}F{sub 2}, which possess considerable ion conductivity at higher temperatures, have been reported recently. Here, we describe the characterisation of these compounds by solid-state {sup 11}B NMR spectroscopy. The complex central-transition MAS spectra, resulting from overlap of sub-spectra contributed by the individual boron species in the crystal structures, could be clearly separated by acquisition and analysis of 3QMAS spectra. By numerical fit of these sub-spectra, the isotropic chemical shift {delta}{sub iso}, the quadrupolar coupling constant {chi}, and the asymmetry {eta} were determined. Using known relations between boron coordination and chemical shift as well as quadrupolar coupling, the individual {sup 11}B NMR resonances have been ascribed to boron species in tetrahedral or trigonal environment. To remove remaining assignment ambiguities, the response of the {sup 11}B resonances to {sup 19}F decoupling was qualitatively analysed. Thus, by using the combined information conveyed by chemical shift, quadrupolar and dipolar interaction, a complete assignment of the complex {sup 11}B line shapes exhibited by the fluorooxoborates has been achieved. - Graphical abstract: Structure and solid-state {sup 11}B NMR spectrum of Li{sub 2}B{sub 3}O{sub 4}F{sub 3}. Highlights: Black-Right-Pointing-Pointer Characterisation of title compounds by solid-state {sup 11}B NMR spectroscopy. Black-Right-Pointing-Pointer Sub-spectra of boron species separated by evaluation of 3QMAS spectra. Black-Right-Pointing-Pointer Isotropic chemical shift and quadrupolar interaction parameters determined. Black-Right-Pointing-Pointer Full boron assignment based on NMR parameters and response to {sup 19}F decoupling.

  12. Estimation of the specific surface area of apatites in human mineralized tissues using 31P MAS NMR.

    PubMed

    Kolmas, Joanna; Slósarczyk, Anna; Wojtowicz, Andrzej; Kolodziejski, Waclaw

    2007-10-01

    Specific surface areas of apatites in whole human mineralized tissues were estimated from (31)P MAS NMR linewidths: 77 m(2)g(-1) for enamel and 94 m(2)g(-1) for dentin, dental cementum and cortical bone.

  13. Determination of the bond-angle distribution in vitreous B{sub 2}O{sub 3} by {sup 11}B double rotation (DOR) NMR spectroscopy

    SciTech Connect

    Hung, I.; Howes, A.P.; Parkinson, B.G.; Anupold, T.; Samoson, A.; Brown, S.P.; Harrison, P.F.; Holland, D.; Dupree, R.

    2009-09-15

    The B-O-B bond angle distributions for both ring and non-ring boron sites in vitreous B{sub 2}O{sub 3} have been determined by {sup 11}B double rotation (DOR) NMR and multiple-quantum (MQ) DOR NMR. The [B{sub 3}O{sub 6}] boroxol rings are observed to have a mean internal B-O-B angle of 120.0+-0.7 deg. with a small standard deviation, sigma{sub R}=3.2+-0.4 deg., indicating that the rings are near-perfect planar, hexagonal structures. The rings are linked predominantly by non-ring [BO{sub 3}] units, which share oxygens with the boroxol ring, with a mean B{sub ring}-O-B{sub non-ring} angle of 135.1+-0.6 deg. and sigma{sub NR}=6.7+-0.4 deg. In addition, the fraction of boron atoms, f, which reside in the boroxol rings has been measured for this sample as f=0.73+-0.01. - Graphical abstract: Connectivities and B-O-B bond angle distributions of ring and non-ring boron atoms in v-B{sub 2}O{sub 3} have been determined by {sup 11}B double rotation (DOR) NMR, multiple-quantum (MQ) DOR NMR and spin-diffusion DOR. Near-perfect planar, hexagonal [B{sub 3}O{sub 6}] boroxol rings are shown to be present. Display Omitted

  14. Effects of nucleotide binding to LmrA: A combined MAS-NMR and solution NMR study.

    PubMed

    Hellmich, Ute A; Mönkemeyer, Leonie; Velamakanni, Saroj; van Veen, Hendrik W; Glaubitz, Clemens

    2015-12-01

    ABC transporters are fascinating examples of fine-tuned molecular machines that use the energy from ATP hydrolysis to translocate a multitude of substrates across biological membranes. While structural details have emerged on many members of this large protein superfamily, a number of functional details are still under debate. High resolution structures yield valuable insights into protein function, but it is the combination of structural, functional and dynamic insights that facilitates a complete understanding of the workings of their complex molecular mechanisms. NMR is a technique well-suited to investigate proteins in atomic resolution while taking their dynamic properties into account. It thus nicely complements other structural techniques, such as X-ray crystallography, that have contributed high-resolution data to the architectural understanding of ABC transporters. Here, we describe the heterologous expression of LmrA, an ABC exporter from Lactococcus lactis, in Escherichia coli. This allows for more flexible isotope labeling for nuclear magnetic resonance (NMR) studies and the easy study of LmrA's multidrug resistance phenotype. We use a combination of solid-state magic angle spinning (MAS) on the reconstituted transporter and solution NMR on its isolated nucleotide binding domain to investigate consequences of nucleotide binding to LmrA. We find that nucleotide binding affects the protein globally, but that NMR is also able to pinpoint local dynamic effects to specific residues, such as the Walker A motif's conserved lysine residue.

  15. Assessing Heterogeneity of Osteolytic Lesions in Multiple Myeloma by 1H HR-MAS NMR Metabolomics

    PubMed Central

    Tavel, Laurette; Fontana, Francesca; Garcia Manteiga, Josè Manuel; Mari, Silvia; Mariani, Elisabetta; Caneva, Enrico; Sitia, Roberto; Camnasio, Francesco; Marcatti, Magda; Cenci, Simone; Musco, Giovanna

    2016-01-01

    Multiple myeloma (MM) is a malignancy of plasma cells characterized by multifocal osteolytic bone lesions. Macroscopic and genetic heterogeneity has been documented within MM lesions. Understanding the bases of such heterogeneity may unveil relevant features of MM pathobiology. To this aim, we deployed unbiased 1H high-resolution magic-angle spinning (HR-MAS) nuclear magnetic resonance (NMR) metabolomics to analyze multiple biopsy specimens of osteolytic lesions from one case of pathological fracture caused by MM. Multivariate analyses on normalized metabolite peak integrals allowed clusterization of samples in accordance with a posteriori histological findings. We investigated the relationship between morphological and NMR features by merging morphological data and metabolite profiling into a single correlation matrix. Data-merging addressed tissue heterogeneity, and greatly facilitated the mapping of lesions and nearby healthy tissues. Our proof-of-principle study reveals integrated metabolomics and histomorphology as a promising approach for the targeted study of osteolytic lesions. PMID:27809247

  16. Immobilization of soluble protein complexes in MAS solid-state NMR: Sedimentation versus viscosity.

    PubMed

    Sarkar, Riddhiman; Mainz, Andi; Busi, Baptiste; Barbet-Massin, Emeline; Kranz, Maximilian; Hofmann, Thomas; Reif, Bernd

    2016-01-01

    In recent years, MAS solid-state NMR has emerged as a technique for the investigation of soluble protein complexes. It was found that high molecular weight complexes do not need to be crystallized in order to obtain an immobilized sample for solid-state NMR investigations. Sedimentation induced by sample rotation impairs rotational diffusion of proteins and enables efficient dipolar coupling based cross polarization transfers. In addition, viscosity contributes to the immobilization of the molecules in the sample. Natural Deep Eutectic Solvents (NADES) have very high viscosities, and can replace water in living organisms. We observe a considerable amount of cross polarization transfers for NADES solvents, even though their molecular weight is too low to yield significant sedimentation. We discuss how viscosity and sedimentation both affect the quality of the obtained experimental spectra. The FROSTY/sedNMR approach holds the potential to study large protein complexes, which are otherwise not amenable for a structural characterization using NMR. We show that using this method, backbone assignments of the symmetric proteasome activator complex (1.1MDa), and high quality correlation spectra of non-symmetric protein complexes such as the prokaryotic ribosome 50S large subunit binding to trigger factor (1.4MDa) are obtained.

  17. Structural analysis of molybdo-zinc-phosphate glasses: Neutron scattering, FTIR, Raman scattering, MAS NMR studies

    NASA Astrophysics Data System (ADS)

    Renuka, C.; Shinde, A. B.; Krishna, P. S. R.; Reddy, C. Narayana

    2016-08-01

    Vitreous samples were prepared in the xMoO3-17ZnO-(83-x) NaPO3 with 35 ≥ x ≥ 55 glass forming system by energy efficient microwave heating method. Structural evolution of the vitreous network was monitored as a function of composition by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), Raman scattering, Magic Angle Spin Nuclear magnetic resonance (MAS NMR) and Neutron scattering. Addition of MoO3 to the ZnO-NaPO3 glass leads to a pronounced increase in glass transition temperature (Tg) suggesting a significant increase in network connectivity and strength. In order to analyze FTIR and Raman scattering, a simple structural model is presented to rationalize the experimental observations. A number of structural units are formed due to network modification, and the resulting glass may be characterized by a network polyhedral with different numbers of unshared corners. 31P MAS NMR confirms a clear distinction between structural species having 3, 2, 1, 0 bridging oxygens (BOs). Further, Neutron scattering studies were used to probe the structure of these glasses. The result suggests that all the investigated glasses have structures based on chains of four coordinated phosphate and six coordinated molybdate units, besides, two different lengths of P-O bonds in tetrahedral phosphate units that are assigned to bonds of the P-atom with terminal and bridging oxygen atoms.

  18. Indirect detection of infinite-speed MAS solid-state NMR spectra

    NASA Astrophysics Data System (ADS)

    Perras, Frédéric A.; Venkatesh, Amrit; Hanrahan, Michael P.; Goh, Tian Wei; Huang, Wenyu; Rossini, Aaron J.; Pruski, Marek

    2017-03-01

    Heavy spin-1/2 nuclides are known to possess very large chemical shift anisotropies that can challenge even the most advanced magic-angle-spinning (MAS) techniques. Wide manifolds of overlapping spinning sidebands and insufficient excitation bandwidths often obfuscate meaningful spectral information and force the use of static, low-resolution solid-state (SS)NMR methods for the characterization of materials. To address these issues, we have merged fast-magic-angle-turning (MAT) and dipolar heteronuclear multiple-quantum coherence (D-HMQC) experiments to obtain D-HMQC-MAT pulse sequences which enable the rapid acquisition of 2D SSNMR spectra that correlate isotropic 1H chemical shifts to the indirectly detected isotropic ;infinite-MAS; spectra of heavy spin-1/2 nuclides. For these nuclides, the combination of fast MAS and 1H detection provides a high sensitivity, which rivals the DNP-enhanced ultra-wideline SSNMR. The new pulse sequences were used to determine the Pt coordination environments in a complex mixture of decomposition products of transplatin and in a metal-organic framework with Pt ions coordinated to the linker ligands.

  19. SLOW-MAS NMR METHODS TO STUDY METABOLIC PROCESSES IN VIVO AND IN VITRO

    SciTech Connect

    Wind, Robert A.; Bertram, Hanne Christine; Hu, Jian Zhi

    2005-09-25

    In vitro and in vivo 1H NMR spectroscopy is widely used to measure metabolic profiles in cells, tissues, animals, and humans and to use them, e.g., for diagnosis and therapy response evaluations. However, the spectra often suffer from poor resolution due to variations in the isotropic bulk magnetic susceptibility present in biological objects, resulting in a broadening of the NMR lines. In principle this broadening can be averaged to zero by the technique of magic angle spinning (MAS), where the sample is rotated about an axis making an angle of 54o44’ relative to the external magnetic field. However, a problem is that in a standard MAS experiment spinning speeds of a kHz or more are required in order to avoid the occurrence of spinning sidebands (SSBs) in the spectra, which renders analysis of the spectra difficult again. At these spinning speeds the large centrifugal forces cause severe structural damage in larger biological objects, so that this method cannot be used to study metabolic processes in intact samples. In solid state NMR several methods have been developed where slow MAS is combined with special radio frequency pulse sequences to eliminate spinning side bands or separate them from the isotropic spectrum so that a SSB-free high-resolution isotropic spectrum is obtained. It has been shown recently that two methods, phase-adjusted spinning sidebands (PASS) and phase-corrected magic angle turning (PHORMAT), can successfully be modified for applications in biological materials (1, 2). With PASS MAS speeds as low as 40 Hz can be employed, allowing non or minimally invasive in vitro studies of excised tissues and organs. This method was used, amongst other things, to study post mortem changes in the proton metabolite spectra in excised rabbit muscle tissue (3). With PHORMAT the NMR sensitivity is reduced and longer measuring times are required, but with this methodology the MAS speed can be reduced to ~1 Hz. This makes PHORMAT amenable for in vivo

  20. Lipid Bilayer-Bound Conformation of an Integral Membrane Beta Barrel Protein by Multidimensional MAS NMR

    PubMed Central

    Eddy, Matthew T.; Su, Yongchao; Silvers, Robert; Andreas, Loren; Clark, Lindsay; Wagner, Gerhard; Pintacuda, Guido; Emsley, Lyndon; Griffin, Robert G.

    2015-01-01

    The human voltage dependent anion channel 1 (VDAC) is a 32 kDa β-barrel integral membrane protein that controls the transport of ions across the outer mitochondrial membrane. Despite the determination of VDAC solution and diffraction structures, a structural basis for the mechanism of its function is not yet fully understood. Biophysical studies suggest VDAC requires a lipid bilayer to achieve full function, motivating the need for atomic resolution structural information of VDAC in a membrane environment. Here we report an essential step toward that goal: extensive assignments of backbone and side chain resonances for VDAC in DMPC lipid bilayers via magic angle spinning nuclear magnetic resonance (MAS NMR). VDAC reconstituted into DMPC lipid bilayers spontaneously forms 2-dimensional lipid crystals, showing remarkable spectral resolution (0.5–0.3 ppm for 13C line width and less than 0.5 ppm 15N line widths at 750 MHz). In addition to the benefits of working in a lipid bilayer, several distinct advantages are observed with the lipid crystalline preparation. First, the strong signals and sharp line widths facilitated extensive NMR resonance assignments for an integral membrane β-barrel protein in lipid bilayers by MAS NMR. Second, a large number of residues in loop regions were readily observed and assigned, which can be challenging in detergent-solubilized membrane proteins where loop regions are often not detected due to line broadening from conformational exchange. Third, complete backbone and side chain chemical shift assignments could be obtained for the first 25 residues, which comprise the functionally important N-terminus. The reported assignments allow us to compare predicted torsion angles for VDAC prepared in DMPC 2D lipid crystals, DMPC liposomes, and LDAO-solubilized samples to address the possible effects of the membrane mimetic environment on the conformation of the protein. Concluding, we discuss the strengths and weaknesses of the reported

  1. Lipid bilayer-bound conformation of an integral membrane beta barrel protein by multidimensional MAS NMR.

    PubMed

    Eddy, Matthew T; Su, Yongchao; Silvers, Robert; Andreas, Loren; Clark, Lindsay; Wagner, Gerhard; Pintacuda, Guido; Emsley, Lyndon; Griffin, Robert G

    2015-04-01

    The human voltage dependent anion channel 1 (VDAC) is a 32 kDa β-barrel integral membrane protein that controls the transport of ions across the outer mitochondrial membrane. Despite the determination of VDAC solution and diffraction structures, a structural basis for the mechanism of its function is not yet fully understood. Biophysical studies suggest VDAC requires a lipid bilayer to achieve full function, motivating the need for atomic resolution structural information of VDAC in a membrane environment. Here we report an essential step toward that goal: extensive assignments of backbone and side chain resonances for VDAC in DMPC lipid bilayers via magic angle spinning nuclear magnetic resonance (MAS NMR). VDAC reconstituted into DMPC lipid bilayers spontaneously forms two-dimensional lipid crystals, showing remarkable spectral resolution (0.5-0.3 ppm for (13)C line widths and <0.5 ppm (15)N line widths at 750 MHz). In addition to the benefits of working in a lipid bilayer, several distinct advantages are observed with the lipid crystalline preparation. First, the strong signals and sharp line widths facilitated extensive NMR resonance assignments for an integral membrane β-barrel protein in lipid bilayers by MAS NMR. Second, a large number of residues in loop regions were readily observed and assigned, which can be challenging in detergent-solubilized membrane proteins where loop regions are often not detected due to line broadening from conformational exchange. Third, complete backbone and side chain chemical shift assignments could be obtained for the first 25 residues, which comprise the functionally important N-terminus. The reported assignments allow us to compare predicted torsion angles for VDAC prepared in DMPC 2D lipid crystals, DMPC liposomes, and LDAO-solubilized samples to address the possible effects of the membrane mimetic environment on the conformation of the protein. Concluding, we discuss the strengths and weaknesses of the reported

  2. MAS NMR, DRIFT, and FT-Raman Characterization of SiO(2)-AlPO(4)-B(2)O(3) Ternary Catalytic Systems.

    PubMed

    Aramendía; Boráu; Jiménez; Marinas; Ruiz; Urbano

    1999-09-01

    This work deals with the preparation of SiO(2)-AlPO(4)-B(2)O(3) ternary systems from impregation of a SiO(2)-AlPO(4) solid previously synthesized with B(OH)(3) (0-10% B(OH)(3), by weight). Characterization of the resulting solids has been carried out from adsorption-desorption isotherms of nitrogen, DRIFT, FT-Raman, pyridine adsorption, and (1)H, (11)B, (27)Al, and (31)P MAS NMR. The textural properties are scarcely changed by the impregnation and calcination steps. Moreover, the MAS NMR experiments indicated that the components of the solids do not interact among them. The solids were tested in the dehydration-dehydrogenation of propan-2-ol, widely used to correlate catalytic activity with the surface acid-base properties of the solids. The catalytic results indicate that the effect of boron dopping is an increase in the overall acidity of the solids. Copyright 1999 Academic Press.

  3. MAS (1)H NMR Probes Freezing Point Depression of Water and Liquid-Gel Phase Transitions in Liposomes.

    PubMed

    Mandal, Abhishek; van der Wel, Patrick C A

    2016-11-01

    The lipid bilayer typical of hydrated biological membranes is characterized by a liquid-crystalline, highly dynamic state. Upon cooling or dehydration, these membranes undergo a cooperative transition to a rigidified, more-ordered, gel phase. This characteristic phase transition is of significant biological and biophysical interest, for instance in studies of freezing-tolerant organisms. Magic-angle-spinning (MAS) solid-state NMR (ssNMR) spectroscopy allows for the detection and characterization of the phase transitions over a wide temperature range. In this study we employ MAS (1)H NMR to probe the phase transitions of both solvent molecules and different hydrated phospholipids, including tetraoleoyl cardiolipin (TOCL) and several phosphatidylcholine lipid species. The employed MAS NMR sample conditions cause a previously noted substantial reduction in the freezing point of the solvent phase. The effect on the solvent is caused by confinement of the aqueous solvent in the small and densely packed MAS NMR samples. In this study we report and examine how the freezing point depression also impacts the lipid phase transition, causing a ssNMR-observed reduction in the lipids' melting temperature (Tm). The molecular underpinnings of this phenomenon are discussed and compared with previous studies of membrane-associated water phases and the impact of membrane-protective cryoprotectants.

  4. Structural study of synthetic mica montmorillonite by means of 2D MAS NMR experiments

    NASA Astrophysics Data System (ADS)

    Alba, M. D.; Castro, M. A.; Chain, P.; Naranjo, M.; Perdigón, A. C.

    2005-07-01

    Syn-1, is a synthetic mica montmorillonite interstratified mineral that forms one of the standard clay samples in the Clay Minerals Society Source Clays Project. However, there are still controversies regarding some structural aspects such as the interlayer composition or the location of the extra-aluminium determined by chemical analysis. The main objective of this paper is to shed light on those structural aspects that affect the reactivity of the interstratified minerals. For this purpose, we have used 1 H 29 Si and 1 H 27Al HETCOR MAS NMR to show that it is likely that the interlayer space of the beidellite part is composed of ammonium ions whereas ammonium and aluminium ions are responsible for the charge balance in the mica type layer.

  5. Molecular degradation of ancient documents revealed by 1H HR-MAS NMR spectroscopy

    PubMed Central

    Corsaro, Carmelo; Mallamace, Domenico; Łojewska, Joanna; Mallamace, Francesco; Pietronero, Luciano; Missori, Mauro

    2013-01-01

    For centuries mankind has stored its knowledge on paper, a remarkable biomaterial made of natural cellulose fibers. However, spontaneous cellulose degradation phenomena weaken and discolorate paper over time. The detailed knowledge of products arising from cellulose degradation is essential in understanding deterioration pathways and in improving durability of cultural heritage. In this study, for the first time, products of cellulose degradation were individually detected in solid paper samples by means of an extremely powerful proton HR-MAS NMR set-up, in combination to a wise use of both ancient and, as reference, artificially aged paper samples. Carboxylic acids, in addition to more complex dicarboxylic and hydroxy-carboxylic acids, were found in all samples studied. Since these products can catalyze further degradation, their knowledge is fundamental to improve conservation strategies of historical documents. Furthermore, the identification of compounds used in ancient production techniques, also suggests for artifacts dating, authentication and provenance. PMID:24104201

  6. Higher Order Amyloid Fibril Structure by MAS NMR and DNP Spectroscopy

    PubMed Central

    Debelouchina, Galia T.; Bayro, Marvin J.; Fitzpatrick, Anthony W.; Ladizhansky, Vladimir; Colvin, Michael T.; Caporini, Marc A.; Jaroniec, Christopher P.; Bajaj, Vikram S.; Rosay, Melanie; MacPhee, Cait E.; Vendruscolo, Michele; Maas, Werner E.; Dobson, Christopher M.; Griffin, Robert G.

    2014-01-01

    Protein magic angle spinning (MAS) NMR spectroscopy has generated structural models of several amyloid fibril systems, thus providing valuable information regarding the forces and interactions that confer the extraordinary stability of the amyloid architecture. Despite these advances, however, obtaining atomic resolution information describing the higher levels of structural organization within the fibrils remains a significant challenge. Here, we detail MAS NMR experiments and sample labeling schemes designed specifically to probe such higher order amyloid structure and we have applied them to the fibrils formed by an eleven-residue segment of the amyloidogenic protein transthyretin (TTR(105-115)). These experiments have allowed us to define unambiguously not only the arrangement of the peptide β-strands into β-sheets but also the β-sheet interfaces within each protofilament, and in addition to identify the nature of the protofilament-to-protofilament contacts that lead to the formation of the complete fibril. Our efforts have resulted in 111 quantitative distance and torsion angle restraints (10 per residue) that describe the various levels of structure organization. The experiments benefited extensively from the use of dynamic nuclear polarization (DNP), which in some cases allowed us to shorten the data acquisition time from days to hours and to improve significantly the signal-to-noise ratios of the spectra. The β-sheet interface and protofilament interactions identified here revealed local variations in the structure that result in multiple peaks for the exposed N- and C-termini of the peptide and in inhomogeneous line-broadening for the side-chains buried within the interior of the fibrils. PMID:24304221

  7. Dynamic Nuclear Polarization Enhanced MAS NMR for Structural Analysis of HIV-1 Protein Assemblies

    PubMed Central

    Gupta, Rupal; Lu, Manman; Hou, Guangjin; Caporini, Marc A.; Rosay, Melanie; Maas, Werner; Struppe, Jochem; Suiter, Christopher; Ahn, Jinwoo; Byeon, In-Ja L.; Franks, W. Trent; Orwick-Rydmark, Marcella; Bertarello, Andrea; Oschkinat, Hartmut; Lesage, Anne; Pintacuda, Guido; Gronenborn, Angela M.; Polenova, Tatyana

    2016-01-01

    Mature infectious HIV-1 virions contain conical capsids comprised of CA protein, generated by the proteolytic cleavage cascade of the Gag polyprotein, termed maturation. The mechanism of capsid core formation through the maturation process remains poorly understood. We present DNP-enhanced MAS NMR studies of tubular assemblies of CA and Gag CA-SP1 maturation intermediate and report 20 – 64 fold sensitivity enhancements due to DNP at 14.1 T. These sensitivity enhancements enabled direct observation of spacer peptide 1 (SP1) resonances in CA-SP1 by dipolar based correlation experiments, unequivocally indicating that the SP1 peptide is unstructured in assembled CA-SP1 at cryogenic temperatures, corroborating our earlier results. Furthermore, the dependence of DNP enhancements and spectral resolution on magnetic field strength (9.4 – 18.8 T) and temperature (109 – 180 K) was investigated. Our results suggest that DNP-based measurements could potentially provide residue-specific dynamics information by allowing for the extraction of temperature dependence of the anisotropic tensorial or relaxation parameters. With DNP, we were able to detect multiple well-resolved isoleucine sidechain conformers, unique intermolecular correlations across two CA molecules, and functionally relevant conformationally disordered states such as the 14-residue SP1 peptide, none of which are visible at ambient temperatures. The detection of isolated conformers and intermolecular correlations can provide crucial constraints for structure determination of these assemblies. Overall, our results establish DNP-based MAS NMR as an excellent tool for characterization of HIV-1 assemblies. PMID:26709853

  8. Dynamic Nuclear Polarization Enhanced MAS NMR Spectroscopy for Structural Analysis of HIV-1 Protein Assemblies.

    PubMed

    Gupta, Rupal; Lu, Manman; Hou, Guangjin; Caporini, Marc A; Rosay, Melanie; Maas, Werner; Struppe, Jochem; Suiter, Christopher; Ahn, Jinwoo; Byeon, In-Ja L; Franks, W Trent; Orwick-Rydmark, Marcella; Bertarello, Andrea; Oschkinat, Hartmut; Lesage, Anne; Pintacuda, Guido; Gronenborn, Angela M; Polenova, Tatyana

    2016-01-21

    Mature infectious HIV-1 virions contain conical capsids composed of CA protein, generated by the proteolytic cleavage cascade of the Gag polyprotein, termed maturation. The mechanism of capsid core formation through the maturation process remains poorly understood. We present DNP-enhanced MAS NMR studies of tubular assemblies of CA and Gag CA-SP1 maturation intermediate and report 20-64-fold sensitivity enhancements due to DNP at 14.1 T. These sensitivity enhancements enabled direct observation of spacer peptide 1 (SP1) resonances in CA-SP1 by dipolar-based correlation experiments, unequivocally indicating that the SP1 peptide is unstructured in assembled CA-SP1 at cryogenic temperatures, corroborating our earlier results. Furthermore, the dependence of DNP enhancements and spectral resolution on magnetic field strength (9.4-18.8 T) and temperature (109-180 K) was investigated. Our results suggest that DNP-based measurements could potentially provide residue-specific dynamics information by allowing for the extraction of the temperature dependence of the anisotropic tensorial or relaxation parameters. With DNP, we were able to detect multiple well-resolved isoleucine side-chain conformers; unique intermolecular correlations across two CA molecules; and functionally relevant conformationally disordered states such as the 14-residue SP1 peptide, none of which are visible at ambient temperatures. The detection of isolated conformers and intermolecular correlations can provide crucial constraints for structure determination of these assemblies. Overall, our results establish DNP-based MAS NMR spectroscopy as an excellent tool for the characterization of HIV-1 assemblies.

  9. Assessing the fate and transformation of plant residues in the terrestrial environment using HR-MAS NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Kelleher, Brian P.; Simpson, Myrna J.; Simpson, Andre J.

    2006-08-01

    Plant litter decomposition plays a fundamental role in carbon and nitrogen cycles, provides key nutrients to the soil environment and represents a potentially large positive feedback to atmospheric CO 2. However, the full details of decomposition pathways and products are unknown. Here we present the first application of HR-MAS NMR spectroscopy on 13C and 15N labeled plant materials, and apply this approach in a preliminary study to monitor the environmental degradation of the pine and wheatgrass residues over time. In HR-MAS, is it possible to acquire very high resolution NMR data of plant biomass, and apply the vast array of multidimensional experiments available in conventional solution-state NMR. High levels of isotopic enrichment combined with HR-MAS significantly enhance the detection limits, and provide a wealth of information that is unattainable by any other method. Diffusion edited HR-MAS NMR data reveal the rapid loss of carbohydrate structures, while two-dimensional (2-D) HR-MAS NMR spectra demonstrate the relatively fast loss of both hydrolysable and condensed tannin structures from all plant tissues studied. Aromatic (partially lignin) and aliphatic components (waxes, cuticles) tend to persist, along with a small fraction of carbohydrate, and become highly functionalized over time. While one-dimensional (1-D) 13C HR-MAS NMR spectra of fresh plant tissue reflect compositional differences between pine and grass, these differences become negligible after decomposition suggesting that recalcitrant carbon may be similar despite the plant source. Two-dimensional 1H- 15N HR-MAS NMR analysis of the pine residue suggests that nitrogen from specific peptides is either selectively preserved or used for the synthesis of what appears to be novel structures. The amount of relevant data generated from plant components in situ using HR-MAS NMR is highly encouraging, and demonstrates that complete assignment will yield unprecedented structural knowledge of plant cell

  10. Technetium-99 MAS NMR spectroscopy of a cationic framework material that traps TcO4- ions

    SciTech Connect

    Yu, P.; Wang, Shuao; Alekseev, Evgeny V.; Depmeier, Wulf; Albrecht-Schmitt, Thomas E.; Phillips, Brian L.; Casey, William H.

    2010-07-15

    99Tc magic-angle spinning (MAS) NMR spectra show that TcO4- ions, which are generated by nuclear fission and can contaminate the environment, can be trapped within the channels and cavities of a cationic framework material (see picture). These spectra are among the first 99Tc MAS NMR spectra reported to date, and show that the TcO4- ions can be efficiently removed from simulated nuclear waste solutions.

  11. Thermal maturity of type II kerogen from the New Albany Shale assessed by 13C CP/MAS NMR.

    PubMed

    Werner-Zwanziger, Ulrike; Lis, Grzegorz; Mastalerz, Maria; Schimmelmann, Arndt

    2005-01-01

    Thermal maturity of oil and gas source rocks is typically quantified in terms of vitrinite reflectance, which is based on optical properties of terrestrial woody remains. This study evaluates 13C CP/MAS NMR parameters in kerogen (i.e., the insoluble fraction of organic matter in sediments and sedimentary rocks) as proxies for thermal maturity in marine-derived source rocks where terrestrially derived vitrinite is often absent or sparse. In a suite of samples from the New Albany Shale (Middle Devonian to the Early Mississippian, Illinois Basin) the abundance of aromatic carbon in kerogen determined by 13C CP/MAS NMR correlates linearly well with vitrinite reflectance.

  12. 1H HR-MAS NMR of carotenoids in aqueous samples and raw vegetables.

    PubMed

    Miglietta, M L; Lamanna, R

    2006-07-01

    Carotenoids are linear C40 tetraterpenoid hydrocarbons and represent a wide category of natural pigments. They are components of the pigment system of chloroplasts and are involved in the primary light absorption and the photon canalization of photosynthesis. Moreover, they also behave as quenchers of singlet oxygen, protecting cells and organisms against lipid peroxidation. Carotenoids have a strong lipophilic character and are usually analyzed in organic solvents. However, because of their biological activity, the characterization of these compounds in an aqueous environment or in the natural matrix is very important. One of the most important dietary carotenoids is beta-carotene, which has been extensively studied both in vivo and in model systems, but because of the low concentration and strong interaction with the biological matrix, beta-carotene has never been observed by NMR in solid aqueous samples.In the present work, a model system has been developed for the detection and identification of beta-carotene in solid aqueous samples by 1H HR-MAS NMR. The efficiency of the model has led to the identification of beta-carotene in a raw vegetable matrix.

  13. Evidence for cross-linking in tomato cutin using HR-MAS NMR spectroscopy.

    PubMed

    Deshmukh, Ashish P; Simpson, André J; Hatcher, Patrick G

    2003-11-01

    Cutin is a polyester biopolymer component of plant leaf and fruit cuticles, most often associated with waxes and cuticular polysaccharides, and sometimes with another aliphatic biopolymer called cutan. Insolubility of these cuticular biopolymers has made it difficult to apply traditional analytical techniques for structure determination, because most techniques providing molecular level details require solubility. By using the relatively new technique of one and two-dimensional high-resolution magic angle spinning (HR-MAS) NMR spectroscopy, with added information from solid-state 13C NMR spectroscopy, detailed through-bond connectivities and assignments are made for cutin from Lycopersicon esculentum (tomato) fruit. Based on the data obtained, tomato cutin is found to be predominantly an aliphatic polyester with some olefinic and aromatic moieties, consistent with previous studies that employed various degradative approaches. Aside from esters, there are free primary and secondary alcohol groups, as well as free fatty acids. A significant finding is the presence of alpha-branched fatty acids/esters. Mid-chain hydroxyls appear to be generally unesterified, but esters of mid-chain hydroxyls have been identified. The alpha-branched fatty acids/esters and esters of mid-chain hydroxyls could point towards cross-linking.

  14. Magnetization-recovery experiments for static and MAS-NMR of I = 3/2 nuclei

    NASA Astrophysics Data System (ADS)

    Yesinowski, James P.

    2006-05-01

    Multifrequency pulsed NMR experiments on quadrupole-perturbed I = 3/2 spins in single crystals are shown to be useful for measuring spin-lattice relaxation parameters even for a mixture of quadrupolar plus magnetic relaxation mechanisms. Such measurements can then be related to other MAS-NMR experiments on powders. This strategy is demonstrated by studies of 71Ga and 69Ga (both I = 3/2) spin-lattice relaxation behavior in a single-crystal (film) sample of gallium nitride, GaN, at various orientations of the axially symmetric nuclear quadrupole coupling tensor. Observation of apparent single-exponential relaxation behavior in I = 3/2 saturation-recovery experiments can be misleading when individual contributing rate processes are neglected in the interpretation. The quadrupolar mechanism (dominant in this study) has both a single-quantum process ( T1Q1) and a double-quantum process ( T1Q2), whose time constants are not necessarily equal. Magnetic relaxation (in this study most likely arising from hyperfine couplings to unpaired delocalized electron spins in the conduction band) also contributes to a single-quantum process ( T1M). A strategy of multifrequency irradiation with observation of satellite and/or central transitions, incorporating different initial conditions for the level populations, provides a means of obtaining these three relaxation time constants from single-crystal 71Ga data alone. The 69Ga results provide a further check of internal consistency, since magnetic and quadrupolar contributions to its relaxation scale in opposite directions compared to 71Ga. For both perpendicular and parallel quadrupole coupling tensor symmetry axis orientations small but significant differences between T1Q1 and T1Q2 were measured, whereas for a tensor symmetry axis oriented at the magic-angle (54.74°) the values were essentially equal. Magic-angle spinning introduces a number of complications into the measurement and interpretation of the spin-lattice relaxation

  15. Characterization of cation environments in polycrystalline forsterite by Mg-25 MAS, MQMAS, and QCPMG NMR

    SciTech Connect

    Davis, Michael C.; Brouwer, William J.; Lipton, Andrew S.; Gan, Zhehong; Mueller, Karl T.

    2010-11-01

    Forsterite (Mg2SiO4) is a silicate mineral frequently studied in the Earth sciences as it has a simple crystal structure and fast dissolution kinetics (elemental release rates under typical conditions on the order of 10-7 mol/m2/s1). During the dissolution process, spectroscopic techniques are often utilized to augment solution chemical analysis and to provide data for determining reaction mechanisms. Nuclear magnetic resonance (NMR) is able to interrogate the local bonding arrangement and coordination of a particular nuclide to obtain in structural information. Although previous NMR studies have focused on the silicon and oxygen environments in forsterite, studies focusing on the two nonequivalent magnesium environments in forsterite are limited to a few single-crystal studies. In this study, we present the results of 25Mg MAS, MQMAS, and static QCMG experiments performed on a powdered sample of pure synthetic forsterite. We also present spectral fits obtained from simulation software packages, which directly provide quadrupolar parameters for 25Mg nuclei occupying each of the two nonequivalent magnesium sites in the forsterite structure. These results are compared to calculations of the electric field gradient tenor conducted in previous ab initio studies to make definitive assignments correlating each peak to their respective magnesium site in the forsterite structure. Although previous NMR investigations of forsterite have focused on single-crystal samples, we have focused on powdered forsterite as the increased surface area of powdered samples makes them more amenable to laboratory-scale dissolution studies and, ultimately, the products from chemical weathering may be monitored an quantified.

  16. Heating and temperature gradients of lipid bilayer samples induced by RF irradiation in MAS solid-state NMR experiments.

    PubMed

    Wang, Jing; Zhang, Zhengfeng; Zhao, Weijing; Wang, Liying; Yang, Jun

    2016-05-09

    The MAS solid-state NMR has been a powerful technique for studying membrane proteins within the native-like lipid bilayer environment. In general, RF irradiation in MAS NMR experiments can heat and potentially destroy expensive membrane protein samples. However, under practical MAS NMR experimental conditions, detailed characterization of RF heating effect of lipid bilayer samples is still lacking. Herein, using (1) H chemical shift of water for temperature calibration, we systematically study the dependence of RF heating on hydration levels and salt concentrations of three lipids in MAS NMR experiments. Under practical (1) H decoupling conditions used in biological MAS NMR experiments, three lipids show different dependence of RF heating on hydration levels as well as salt concentrations, which are closely associated with the properties of lipids. The maximum temperature elevation of about 10 °C is similar for the three lipids containing 200% hydration, which is much lower than that in static solid-state NMR experiments. The RF heating due to salt is observed to be less than that due to hydration, with a maximum temperature elevation of less than 4 °C in the hydrated samples containing 120 mmol l(-1) of salt. Upon RF irradiation, the temperature gradient across the sample is observed to be greatly increased up to 20 °C, as demonstrated by the remarkable broadening of (1) H signal of water. Based on detailed characterization of RF heating effect, we demonstrate that RF heating and temperature gradient can be significantly reduced by decreasing the hydration levels of lipid bilayer samples from 200% to 30%. Copyright © 2016 John Wiley & Sons, Ltd.

  17. 11B and 27Al NMR spin-lattice relaxation and Knight shift of Mg1-xAlxB2: Evidence for an anisotropic Fermi surface

    NASA Astrophysics Data System (ADS)

    Papavassiliou, G.; Pissas, M.; Karayanni, M.; Fardis, M.; Koutandos, S.; Prassides, K.

    2002-10-01

    We report a detailed study of the 11B and 27Al NMR spin-lattice relaxation rates (1/T1) and the 27Al Knight shift (K) in Mg1-xAlxB2, 0<=x<=1. The evolution of (1/T1T) and K with x is in excellent agreement with the prediction of ab initio calculations of a highly anisotropic Fermi surface, consisting mainly of hole-type two-dimensional (2D) cylindrical sheets from bonding 2px,y boron orbitals. The density of states at the Fermi level also decreases sharply on Al doping and the 2D sheets collapse at x~0.55, where the superconducting phase disappears.

  18. Fermi resonance of C 1 chlorine compounds in the adsorbed phase of zeolites. An FTIR and MAS NMR spectroscopic study

    NASA Astrophysics Data System (ADS)

    Hannus, I.; Kónya, Z.; Nagy, J. B.; Kiricsi, I.

    1997-06-01

    Fermi resonance was investigated for CH 3Cl, COCl 2, CO + Cl 2, CCl 4 and CCl 2F 2 adsorbed in NaYFAU zeolite. The extent of the resonance was measured by IR spectroscopy, while the mechanism of surface reaction was evidenced by MAS NMR spectroscopy.

  19. Proton chemical shift tensors determined by 3D ultrafast MAS double-quantum NMR spectroscopy

    SciTech Connect

    Zhang, Rongchun; Mroue, Kamal H.; Ramamoorthy, Ayyalusamy

    2015-10-14

    Proton NMR spectroscopy in the solid state has recently attracted much attention owing to the significant enhancement in spectral resolution afforded by the remarkable advances in ultrafast magic angle spinning (MAS) capabilities. In particular, proton chemical shift anisotropy (CSA) has become an important tool for obtaining specific insights into inter/intra-molecular hydrogen bonding. However, even at the highest currently feasible spinning frequencies (110–120 kHz), {sup 1}H MAS NMR spectra of rigid solids still suffer from poor resolution and severe peak overlap caused by the strong {sup 1}H–{sup 1}H homonuclear dipolar couplings and narrow {sup 1}H chemical shift (CS) ranges, which render it difficult to determine the CSA of specific proton sites in the standard CSA/single-quantum (SQ) chemical shift correlation experiment. Herein, we propose a three-dimensional (3D) {sup 1}H double-quantum (DQ) chemical shift/CSA/SQ chemical shift correlation experiment to extract the CS tensors of proton sites whose signals are not well resolved along the single-quantum chemical shift dimension. As extracted from the 3D spectrum, the F1/F3 (DQ/SQ) projection provides valuable information about {sup 1}H–{sup 1}H proximities, which might also reveal the hydrogen-bonding connectivities. In addition, the F2/F3 (CSA/SQ) correlation spectrum, which is similar to the regular 2D CSA/SQ correlation experiment, yields chemical shift anisotropic line shapes at different isotropic chemical shifts. More importantly, since the F2/F1 (CSA/DQ) spectrum correlates the CSA with the DQ signal induced by two neighboring proton sites, the CSA spectrum sliced at a specific DQ chemical shift position contains the CSA information of two neighboring spins indicated by the DQ chemical shift. If these two spins have different CS tensors, both tensors can be extracted by numerical fitting. We believe that this robust and elegant single-channel proton-based 3D experiment provides useful atomistic

  20. Proton chemical shift tensors determined by 3D ultrafast MAS double-quantum NMR spectroscopy.

    PubMed

    Zhang, Rongchun; Mroue, Kamal H; Ramamoorthy, Ayyalusamy

    2015-10-14

    Proton NMR spectroscopy in the solid state has recently attracted much attention owing to the significant enhancement in spectral resolution afforded by the remarkable advances in ultrafast magic angle spinning (MAS) capabilities. In particular, proton chemical shift anisotropy (CSA) has become an important tool for obtaining specific insights into inter/intra-molecular hydrogen bonding. However, even at the highest currently feasible spinning frequencies (110-120 kHz), (1)H MAS NMR spectra of rigid solids still suffer from poor resolution and severe peak overlap caused by the strong (1)H-(1)H homonuclear dipolar couplings and narrow (1)H chemical shift (CS) ranges, which render it difficult to determine the CSA of specific proton sites in the standard CSA/single-quantum (SQ) chemical shift correlation experiment. Herein, we propose a three-dimensional (3D) (1)H double-quantum (DQ) chemical shift/CSA/SQ chemical shift correlation experiment to extract the CS tensors of proton sites whose signals are not well resolved along the single-quantum chemical shift dimension. As extracted from the 3D spectrum, the F1/F3 (DQ/SQ) projection provides valuable information about (1)H-(1)H proximities, which might also reveal the hydrogen-bonding connectivities. In addition, the F2/F3 (CSA/SQ) correlation spectrum, which is similar to the regular 2D CSA/SQ correlation experiment, yields chemical shift anisotropic line shapes at different isotropic chemical shifts. More importantly, since the F2/F1 (CSA/DQ) spectrum correlates the CSA with the DQ signal induced by two neighboring proton sites, the CSA spectrum sliced at a specific DQ chemical shift position contains the CSA information of two neighboring spins indicated by the DQ chemical shift. If these two spins have different CS tensors, both tensors can be extracted by numerical fitting. We believe that this robust and elegant single-channel proton-based 3D experiment provides useful atomistic-level structural and dynamical

  1. 13C CP/MAS NMR studies of vitamin E model compounds.

    PubMed

    Witkowski, Stanislaw; Paradowska, Katarzyna; Wawer, Iwona

    2004-10-01

    13C cross-polarization magic angle spinning (CP/MAS) NMR data for 2,2,5,7,8-pentamethylchroman-6-ol (2), 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox c) (3) and its acetate (4), 2-methoxy-2,2,5,7,8-pentamethylchroman-6-ol (5), 2-hydroxy-2,2,5,7,8-pentamethylchroman-6-ol (6) and 2,2,5,7,8-pentamethylchroman (7) are reported. A deshielding of 7.7 ppm for the carboxylic carbon was observed in solid Trolox due to formation of intermolecular hydrogen bonds within cyclic dimers. Such crystal packing permits effective cross-polarization and fast relaxation (short T1rho(H)). The impact of the proton concentration on the CP dynamics is reflected by the longer T(CP) and T1rhoH for Trolox-d2 (deuterated at mobile proton sites). The calculated GIAO RHF shielding constants are sensitive to intramolecular effects: rotation around the C-6-O bond (changes of sigma up to 8 ppm) and conformation at C-2.

  2. Hydration properties of regioselectively etherified celluloses monitored by 2H and 13C solid-state MAS NMR spectroscopy.

    PubMed

    Larsen, Flemming H; Schöbitz, Michael; Schaller, Jens

    2012-06-20

    The hydration properties of 2,3-O-hydroxypropylcellulose (HPC) and 2,3-O-hydroxyethylcellulose (HEC) were analyzed by multi-nuclear solid-state MAS NMR spectroscopy. By 13C single-pulse (SP) MAS and cross-polarization (CP) MAS NMR, differences between the immobile regions and all parts of the polysaccharides were detected as a function of hydration. Complementary information about the water environments was observed by 2H MAS NMR. By this approach it was demonstrated that side chains in 2,3-O-HPC and 2,3-O-HEC were easier to hydrate than the cellulose backbone. Furthermore the motion of water was more restricted (slower) in 2,3-O-HPC than in 2,3-O-HEC. For both polysaccharides the hydration could be explained by a two-step process: in step one increased ordering of the immobile regions occurs after which the entire polymer is hydrated in step two.

  3. High-resolution (19)F MAS NMR spectroscopy: structural disorder and unusual J couplings in a fluorinated hydroxy-silicate.

    PubMed

    Griffin, John M; Yates, Jonathan R; Berry, Andrew J; Wimperis, Stephen; Ashbrook, Sharon E

    2010-11-10

    High-resolution (19)F magic angle spinning (MAS) NMR spectroscopy is used to study disorder and bonding in a crystalline solid. (19)F MAS NMR reveals four distinct F sites in a 50% fluorine-substituted deuterated hydrous magnesium silicate (clinohumite, 4Mg(2)SiO(4)·Mg(OD(1-x)F(x))(2) with x = 0.5), indicating extensive structural disorder. The four (19)F peaks can be assigned using density functional theory (DFT) calculations of NMR parameters for a number of structural models with a range of possible local F environments generated by F(-)/OH(-) substitution. These assignments are supported by two-dimensional (19)F double-quantum MAS NMR experiments that correlate F sites based on either spatial proximity (via dipolar couplings) or through-bond connectivity (via scalar, or J, couplings). The observation of (19)F-(19)F J couplings is unexpected as the fluorines coordinate Mg atoms and the Mg-F interaction is normally considered to be ionic in character (i.e., there is no formal F-Mg-F covalent bonding arrangement). However, DFT calculations predict significant (19)F-(19)F J couplings, and these are in good agreement with the splittings observed in a (19)F J-resolved MAS NMR experiment. The existence of these J couplings is discussed in relation to both the nature of bonding in the solid state and the occurrence of so-called "through-space" (19)F-(19)F J couplings in solution. Finally, we note that we have found similar structural disorder and spin-spin interactions in both synthetic and naturally occurring clinohumite samples.

  4. Partitioning of aluminum atoms in crystallographically non-equivalent tetrahedral sites of the zeolite offretite by 29Si MAS NMR

    NASA Astrophysics Data System (ADS)

    Chen, T. H.; Wang, K. X.; Luo, W. L.; Yuan, Z. Y.; Wang, J. Z.; Ding, D. T.; Li, H. X.; Hu, C.

    1996-04-01

    For the zeolite offretite, a formula is proposed which includes the framework Si/Al ratio ( R), the partitioning ratio of Al over two crystallographically non-equivalent tetrahedral sites ( r) and intensities of the observed peaks in the 29Si MAS NMR spectrum. By this formula, the framework Si/Al ratio of offretite can be estimated from the 29Si MAS NMR spectrum. Combined with chemical analysis of the Si/Al ratio, Al partitioning in two kinds of T sites can also be deduced. It is concluded that the T B sites are favored by Al atoms in parent offretites and Al atoms at T B sites can more easily be substituted isomorphously by Si when treated with (NH 4) 2SiF 6. The formula proposed here is based only on experiments and may be used to testify some statistical models of Al distributions in offretites.

  5. Proton-detected heteronuclear single quantum correlation NMR spectroscopy in rigid solids with ultra-fast MAS

    PubMed Central

    Holland, Gregory P.; Cherry, Brian R.; Jenkins, Janelle E.; Yarger, Jeffery L.

    2009-01-01

    In this article, we show the potential for utilizing proton-detected heteronuclear single quantum correlation (HSQC) NMR in rigid solids under ultra-fast magic angle spinning (MAS) conditions. The indirect detection of carbon-13 from coupled neighboring hydrogen nuclei provides a sensitivity enhancement of 3 - 4 fold in crystalline amino acids over direct-detected versions. Furthermore, the sensitivity enhancement is shown to be significantly larger for disordered solids that display inhomogeneously broadened carbon-13 spectra. Latrodectus hesperus (Black Widow) dragline silk is given as an example where the sample is mass-limited and the sensitivity enhancement for the proton-detected experiment is 8 - 13 fold. The ultra-fast MAS proton-detected HSQC solid-state NMR technique has the added advantage that no proton homonuclear decoupling is applied during the experiment. Further, well-resolved, indirectly observed carbon-13 spectra can be obtained in some cases without heteronuclear proton decoupling. PMID:19857977

  6. Thermal maturity of type II kerogen from the New Albany Shale assessed by13C CP/MAS NMR

    USGS Publications Warehouse

    Werner-Zwanziger, U.; Lis, G.; Mastalerz, Maria; Schimmelmann, A.

    2005-01-01

    Thermal maturity of oil and gas source rocks is typically quantified in terms of vitrinite reflectance, which is based on optical properties of terrestrial woody remains. This study evaluates 13C CP/MAS NMR parameters in kerogen (i.e., the insoluble fraction of organic matter in sediments and sedimentary rocks) as proxies for thermal maturity in marine-derived source rocks where terrestrially derived vitrinite is often absent or sparse. In a suite of samples from the New Albany Shale (Middle Devonian to the Early Mississippian, Illinois Basin) the abundance of aromatic carbon in kerogen determined by 13C CP/MAS NMR correlates linearly well with vitrinite reflectance. ?? 2004 Elsevier Inc. All rights reserved.

  7. DRIFT and HR MAS NMR characterization of humic substances from a soil treated with different organic and mineral fertilizers

    NASA Astrophysics Data System (ADS)

    Ferrari, Erika; Francioso, Ornella; Nardi, Serenella; Saladini, Monica; Ferro, Nicola Dal; Morari, Francesco

    2011-07-01

    In this study, using DRIFT and HR MAS NMR, we analyzed the humic substances isolated from a soil treated, over 40 years, with different organic, mineral and organic plus mineral treatments and cultivated with maize as the main crop. As expected, the structure of humic substances was very complex but by combining both techniques (DRIFT and HR MAS NMR) additional information was obtained on aromatic and aliphatic components, the most recalcitrant parts of these macromolecules. In so doing we wanted to investigate the relationship between HS structure and long-term management practices. An elevated content of lignin, aminoacids, peptides and proteins was observed mainly for farmyard manure treatments with respect to mineral or liquid manure amendments; this supports how the different management practices have greatly influenced the humification process of cultivated soils.

  8. Proton-detected heteronuclear single quantum correlation NMR spectroscopy in rigid solids with ultra-fast MAS.

    PubMed

    Holland, Gregory P; Cherry, Brian R; Jenkins, Janelle E; Yarger, Jeffery L

    2010-01-01

    In this article, we show the potential for utilizing proton-detected heteronuclear single quantum correlation (HSQC) NMR in rigid solids under ultra-fast magic angle spinning (MAS) conditions. The indirect detection of carbon-13 from coupled neighboring hydrogen nuclei provides a sensitivity enhancement of 3- to 4-fold in crystalline amino acids over direct-detected versions. Furthermore, the sensitivity enhancement is shown to be significantly larger for disordered solids that display inhomogeneously broadened carbon-13 spectra. Latrodectus hesperus (Black Widow) dragline silk is given as an example where the sample is mass-limited and the sensitivity enhancement for the proton-detected experiment is 8- to 13-fold. The ultra-fast MAS proton-detected HSQC solid-state NMR technique has the added advantage that no proton homonuclear decoupling is applied during the experiment. Further, well-resolved, indirectly observed carbon-13 spectra can be obtained in some cases without heteronuclear proton decoupling.

  9. MAS-NMR study of lithium zinc silicate glasses and glass-ceramics with various ZnO content

    NASA Astrophysics Data System (ADS)

    Goswami, Madhumita; Kothiyal, Govind P.; Montagne, Lionel; Delevoye, Laurent

    2008-02-01

    Lithium zinc silicate glasses of composition (mol%): 17.5Li 2O-(72- x)SiO 2- xZnO-5.1Na 2O-1.3P 2O 5-4.1B 2O 3, 5.5⩽ x⩽17.7, were prepared by conventional melt-quenched technique and converted to glass-ceramic by controlled crystallization process. 29Si and 31P MAS-NMR was used to characterize the structure of both glass and glass-ceramic samples. Despite the complex glass composition, Q2, Q3 and Q4 sites are identified from 29Si MAS-NMR, which relative intensities are found to vary with the ZnO content, indicating a network depolymerization by ZnO. Moreover, well separated Q3 and Q4 resonances for low ZnO content indicates the occurrence of phase separation. From 31P MAS-NMR, it is seen that phosphorus is mainly present in the form of ortho-( Q0) and pyro-phosphate ( Q1) structural units and variation of ZnO content did not have much effect on these resonances, which provides an additional evidence for phase separation in the glass. On conversion to glass-ceramics, lithium disilicate (Li 2Si 2O 5), lithium zinc ortho-silicate (Li 3Zn 0.5SiO 4), tridymite (SiO 2) and cristobalite (SiO 2) were identified as major silicate crystalline phases. Using 29Si MAS-NMR, quantification of these silicate crystalline phases is carried out and correlated with the ZnO content in the glass-ceramics samples. In addition, 31P spectra unambiguously revealed the presence of crystalline Li 3PO 4 and (Na,Li) 3PO 4 in the glass-ceramics.

  10. Characterization of solid polymer dispersions of active pharmaceutical ingredients by 19F MAS NMR and factor analysis.

    PubMed

    Urbanova, Martina; Brus, Jiri; Sedenkova, Ivana; Policianova, Olivia; Kobera, Libor

    2013-01-01

    In this contribution the ability of (19)F MAS NMR spectroscopy to probe structural variability of poorly water-soluble drugs formulated as solid dispersions in polymer matrices is discussed. The application potentiality of the proposed approach is demonstrated on a moderately sized active pharmaceutical ingredient (API, Atorvastatin) exhibiting extensive polymorphism. In this respect, a range of model systems with the API incorporated in the matrix of polvinylpyrrolidone (PVP) was prepared. The extent of mixing of both components was determined by T(1)((1)H) and T(1ρ)((1)H) relaxation experiments, and it was found that the API forms nanosized domains. Subsequently it was found out that the polymer matrix induces two kinds of changes in (19)F MAS NMR spectra. At first, this is a high-frequency shift reaching 2-3 ppm which is independent on molecular structure of the API and which results from the long-range polarization of the electron cloud around (19)F nucleus induced by electrostatic fields of the polymer matrix. At second, this is broadening of the signals and formation of shoulders reflecting changes in molecular arrangement of the API. To avoid misleading in the interpretation of the recorded (19)F MAS NMR spectra, because both the contributions act simultaneously, we applied chemometric approach based on multivariate analysis. It is demonstrated that factor analysis of the recorded spectra can separate both these spectral contributions, and the subtle structural differences in the molecular arrangement of the API in the nanosized domains can be traced. In this way (19)F MAS NMR spectra of both pure APIs and APIs in solid dispersions can be directly compared. The proposed strategy thus provides a powerful tool for the analysis of new formulations of fluorinated pharmaceutical substances in polymer matrices.

  11. Characterization of solid polymer dispersions of active pharmaceutical ingredients by 19F MAS NMR and factor analysis

    NASA Astrophysics Data System (ADS)

    Urbanova, Martina; Brus, Jiri; Sedenkova, Ivana; Policianova, Olivia; Kobera, Libor

    In this contribution the ability of 19F MAS NMR spectroscopy to probe structural variability of poorly water-soluble drugs formulated as solid dispersions in polymer matrices is discussed. The application potentiality of the proposed approach is demonstrated on a moderately sized active pharmaceutical ingredient (API, Atorvastatin) exhibiting extensive polymorphism. In this respect, a range of model systems with the API incorporated in the matrix of polvinylpyrrolidone (PVP) was prepared. The extent of mixing of both components was determined by T1(1H) and T1ρ(1H) relaxation experiments, and it was found that the API forms nanosized domains. Subsequently it was found out that the polymer matrix induces two kinds of changes in 19F MAS NMR spectra. At first, this is a high-frequency shift reaching 2-3 ppm which is independent on molecular structure of the API and which results from the long-range polarization of the electron cloud around 19F nucleus induced by electrostatic fields of the polymer matrix. At second, this is broadening of the signals and formation of shoulders reflecting changes in molecular arrangement of the API. To avoid misleading in the interpretation of the recorded 19F MAS NMR spectra, because both the contributions act simultaneously, we applied chemometric approach based on multivariate analysis. It is demonstrated that factor analysis of the recorded spectra can separate both these spectral contributions, and the subtle structural differences in the molecular arrangement of the API in the nanosized domains can be traced. In this way 19F MAS NMR spectra of both pure APIs and APIs in solid dispersions can be directly compared. The proposed strategy thus provides a powerful tool for the analysis of new formulations of fluorinated pharmaceutical substances in polymer matrices.

  12. Anomalous spin dynamics in CdCu2(BO3)2 revealed by 11B NMR and ZF-μ SR

    NASA Astrophysics Data System (ADS)

    Lee, W.-J.; Do, S.-H.; Yoon, Sungwon; Jang, Z. H.; Suh, B. J.; Lee, J. H.; Reyes, A. P.; Kuhns, P. L.; Luetkens, H.; Choi, K.-Y.

    2014-12-01

    We report 11B nuclear magnetic resonance (NMR) and zero-field muon spin relaxation (ZF-μ SR ) measurements of the anisotropic spin tetramer system CdCu2(BO3) 2 , which consists of strongly interacting Cu(1) dimers and weakly coupled nonfrustrated Cu(2) spins. Long-range magnetic order is observed at TN=9.8 K by a critical divergence of the nuclear spin-lattice relaxation rate 1 /T1 and an appearance of well-defined muon-spin precessions. In addition, we find the spectroscopic signature for a magnetic anomaly at T*=6.5 K, a few kelvins below TN. For temperatures below T*,1 /T1 ceases to follow a T4.9 (1 ) behavior. Instead, upon cooling below T*, both 1 /T1 and 1 /T2 become temperature-independent with a subsequent small drop. The muon frequency and the relative fraction of the Cu magnetic sites show anomalies mostly for Cu(2) spins at T*. This is ascribed to a Cu(2) spin reorientation. Site-specific change in magnetic structure is discussed in terms of the energy hierarchy of involved exchange interactions and an additional intertetramer interaction that controls magnetism at temperature T*.

  13. Effects of fluoride on in vitro enamel demineralization analyzed by ¹⁹F MAS-NMR.

    PubMed

    Mohammed, N R; Kent, N W; Lynch, R J M; Karpukhina, N; Hill, R; Anderson, P

    2013-01-01

    The mechanistic action of fluoride on inhibition of enamel demineralization was investigated using (19)F magic angle spinning nuclear magnetic resonance (MAS-NMR). The aim of this study was to monitor the fluoride-mineral phase formed on the enamel as a function of the concentration of fluoride ions [F(-)] in the demineralizing medium. The secondary aim was to investigate fluorapatite formation on enamel in the mechanism of fluoride anti-caries efficacy. Enamel blocks were immersed into demineralization solutions of 0.1 M acetic acid (pH 4) with increasing concentrations of fluoride up to 2,262 ppm. At and below 45 ppm [F(-)] in the solution, (19)F MAS-NMR showed fluoride-substituted apatite formation, and above 45 ppm, calcium fluoride (CaF2) formed in increasing proportions. Further increases in [F(-)] caused no further reduction in demineralization, but increased the proportion of CaF2 formed. Additionally, the combined effect of strontium and fluoride on enamel demineralization was also investigated using (19)F MAS-NMR. The presence of 43 ppm [Sr(2+)] in addition to 45 ppm [F(-)] increases the fraction of fluoride-substituted apatite, but delays formation of CaF2 when compared to the demineralization of enamel in fluoride-only solution.

  14. Study of phase transition mechanisms in [N(CH3)4]2ZnCl4 by static NMR and MAS NMR

    NASA Astrophysics Data System (ADS)

    Lim, Ae Ran; Lim, Kye-Young

    2014-05-01

    The temperature dependences of chemical shifts, intensities, the spin-lattice relaxation time in laboratory frame T1, and in rotating frame T1ρ were measured for 1H and 13C in [N(CH3)4]2ZnCl4 by single-crystal NMR and MAS NMR. The unit cell in phase I contains two chemically inequivalent types of N(CH3)4 ions. However, the two chemically different ions N(CH3)4 cannot be practically identified from the 13C NMR spectrum. The structural changes for 1H and 13C were measured near Ti and TC4. The existence of chemically equivalent N(CH3)4 ions in phase I and the existence of the ferroelastic characteristic of the N(CH3)4 ions in phases IV and V are discussed.

  15. Quantitation of crystalline material within a liquid vehicle using 1H/19F CP/MAS NMR.

    PubMed

    Farrer, Brian T; Peresypkin, Andrey; Wenslow, Robert M

    2007-02-01

    A method to detect and quantify a small amount crystalline material within a liquid solution of solubilized material is described. 19F CP-MAS ssNMR was investigated as a technique to detect low levels (0.2 mg/g) of crystalline sodium (2R)-7-{3-[2-chloro-4-(2,2,2-trifluoroethoxy)phenoxy]propoxy}-2-methyl-3,4-dihydro-2H-chromane-2-carboxylate (I) within a solid mixture (with microcrystalline cellulose) and a slurry with a liquid vehicle (capric and caprylic acid triglycerides). The results demonstrate that the area of the 19F CP/MAS signal obtained in 25 min at 25 degrees C is linearly dependent (R2=0.997) on the mass of I within the ssNMR rotor. Slopes of CP-MAS peak area versus mass of I in the rotor were nearly identical for the solid mixture and slurry suspension. Signal-to-noise ratio for the low potency slurry suggest detection and quantitation of 0.1 mg of crystalline I in the rotor, corresponding to 2 mg/g of crystalline material within the slurry suspension.

  16. Determination of the structural changes by Raman and {sup 13}C CP/MAS NMR spectroscopy on native corn starch with plasticizers

    SciTech Connect

    Cozar, O.; Filip, C.; Tripon, C.; Cioica, N.; Coţa, C.; Nagy, E. M.

    2013-11-13

    The plasticizing - antiplasticizing effect of water and glycerol contents on native corn starch samples is investigated by FT-Raman and {sup 13}C CP/MAS NMR spectroscopy. The presence of both amorphous and crystalline structural phases was evidenced in pure native corn starch and also in the samples containing plasticizers. Among the crystalline starch structures, the A- and V- types were suggested by CP/MAS NMR spectra.

  17. 1H HR-MAS NMR Spectroscopy and the Metabolite Determination of Typical Foods in Mediterranean Diet

    PubMed Central

    Corsaro, Carmelo; Mallamace, Domenico; Vasi, Sebastiano; Ferrantelli, Vincenzo; Dugo, Giacomo; Cicero, Nicola

    2015-01-01

    NMR spectroscopy has become an experimental technique widely used in food science. The experimental procedures that allow precise and quantitative analysis on different foods are relatively simple. For a better sensitivity and resolution, NMR spectroscopy is usually applied to liquid sample by means of extraction procedures that can be addressed to the observation of particular compounds. For the study of semisolid systems such as intact tissues, High-Resolution Magic Angle Spinning (HR-MAS) has received great attention within the biomedical area and beyond. Metabolic profiling and metabolism changes can be investigated both in animal organs and in foods. In this work we present a proton HR-MAS NMR study on the typical vegetable foods of Mediterranean diet such as the Protected Geographical Indication (PGI) cherry tomato of Pachino, the PGI Interdonato lemon of Messina, several Protected Designation of Origin (PDO) extra virgin olive oils from Sicily, and the Traditional Italian Food Product (PAT) red garlic of Nubia. We were able to identify and quantify the main metabolites within the studied systems that can be used for their characterization and authentication. PMID:26495154

  18. Microscopic structural analysis of fractured silk fibers from Bombyx mori and Samia cynthia ricini using 13C CP/MAS NMR with a 1mm microcoil MAS NMR probehead.

    PubMed

    Yamauchi, Kazuo; Yamasaki, Shizuo; Takahashi, Rui; Asakura, Tetsuo

    2010-07-01

    Conformational changes have been studied in silk fibers from the domestic silkworm Bombyx mori and a wild silkworm Samia cynthia ricini as a result of fractured by stretching. About 300 samples consisting of only the fractured regions of [1-13C]Ala or [1-13C]Gly labeled silk fibers were collected and observed by 13C CP/MAS NMR spectra. The total amount of these fractured fibers is only about 1mg and therefore we used a home-built 1mm microcoil MAS NMR probehead. A very small increase in the fraction of random coil was noted for the alanine regions of both silk fibroins and for the glycine region of B. mori silk fibroin. However, there is no difference in the spectra before and after fractured for the glycine region of S. c. ricini silk fibroin. Thus, the influence of fracture occurs exclusively at the Ala region for S. c. ricini. The relationship between sequence, fracture and structure is discussed.

  19. Quantification of ammonia binding sites in Davison (Type 3A) zeolite desiccant : a solid-state Nitrogen-15 MAS NMR spectroscopy investigation.

    SciTech Connect

    Alam, Todd Michael; Holland, Gregory P.; Cherry, Brian Ray

    2004-01-01

    The quantitative analysis of ammonia binding sites in the Davison (Type 3A) zeolite desiccant using solid-state {sup 15}N MAS NMR spectroscopy is reported. By utilizing 15N enriched ammonia ({sup 15}NH{sub 3}) gas, the different adsorption/binding sites within the zeolite were investigated as a function of NH{sub 3} loading. Using {sup 15}N MAS NMR multiple sites were resolved that have distinct cross-polarization dynamics and chemical shift behavior. These differences in the {sup 15}N NMR were used to characterize the adsorption environments in both the pure 3A zeolite and the silicone-molded forms of the desiccant.

  20. Site-resolved 2H relaxation experiments in solid materials by global line-shape analysis of MAS NMR spectra

    NASA Astrophysics Data System (ADS)

    Lindh, E. L.; Stilbs, P.; Furó, I.

    2016-07-01

    We investigate a way one can achieve good spectral resolution in 2H MAS NMR experiments. The goal is to be able to distinguish between and study sites in various deuterated materials with small chemical shift dispersion. We show that the 2H MAS NMR spectra recorded during a spin-relaxation experiment are amenable to spectral decomposition because of the different evolution of spectral components during the relaxation delay. We verify that the results are robust by global least-square fitting of the spectral series both under the assumption of specific line shapes and without such assumptions (COmponent-REsolved spectroscopy, CORE). In addition, we investigate the reliability of the developed protocol by analyzing spectra simulated with different combinations of spectral parameters. The performance is demonstrated in a model material of deuterated poly(methacrylic acid) that contains two 2H spin populations with similar chemical shifts but different quadrupole splittings. In 2H-exchanged cellulose containing two 2H spin populations with very similar chemical shifts and quadrupole splittings, the method provides new site-selective information about the molecular dynamics.

  1. CaCl 2 -Accelerated Hydration of Tricalcium Silicate: A STXM Study Combined with 29 Si MAS NMR

    DOE PAGES

    Li, Qinfei; Ge, Yong; Geng, Guoqing; ...

    2015-01-01

    Tmore » he effect of calcium chloride (CaCl 2 ) on tricalcium silicate (C 3 S) hydration was investigated by scanning transmission X-ray microscopy (STXM) with Near Edge X-ray Absorption Fine Structure (NEXAFS) spectra and 29 Si MAS NMR. STXM is demonstrated to be a powerful tool for studying the chemical composition of a cement-based hydration system.he Ca L 3,2 -edge NEXAFS spectra obtained by examining C 3 S hydration in the presence of CaCl 2 showed that this accelerator does not change the coordination of calcium in the calcium silicate hydrate (C-S-H), which is the primary hydration product. O K-edge NEXAFS is also very useful in distinguishing the chemical components in hydrated C 3 S. Based on the Ca L 3,2 -edge spectra and chemical component mapping, we concluded that CaCl 2 prefers to coexist with unhydrated C 3 S instead of C-S-H. In Si K-edge NEXAFS analysis, CaCl 2 increases the degree of silicate polymerization of C-S-H in agreement with the 29 Si CP/MAS NMR results, which show that the presence of CaCl 2 in hydrated C 3 S considerably accelerates the formation of middle groups ( Q 2 ) and branch sites ( Q 3 ) in the silicate chains of C-S-H gel at 1-day hydration.« less

  2. MAS NMR of the Drug Resistant S31N M2 Proton Transporter from Influenza A

    PubMed Central

    Andreas, Loren B.; Eddy, Matthew T.; Chou, James J.; Griffin, Robert G.

    2012-01-01

    We report chemical shift assignments of the drug-resistant S31N mutant of M218-60 determined with magic angle spinning (MAS) 3D spectra acquired with a 15N-13C ZF-TEDOR transfer followed by 13C-13C mixing by RFDR. The MAS spectra reveal two sets of resonances, indicating that the tetramer assembles as a dimer of dimers, similar to the wild type channel. The two sets of chemical shifts are shown to be in close proximity at residue H37, and assignments reveal a difference in the helix torsion angles, as predicted by TALOS+, for the key resistance residue N31. In contrast to wild type M218-60, chemical shift changes are minimal with addition of the inhibitor rimantadine, suggesting that the drug does not bind to S31N. PMID:22480220

  3. Deuterium MAS NMR studies of dynamics on multiple timescales: histidine and oxalic acid.

    PubMed

    Chan-Huot, Monique; Wimperis, Stephen; Gervais, Christel; Bodenhausen, Geoffrey; Duma, Luminita

    2015-01-12

    Deuterium ((2) H) magic-angle spinning (MAS) nuclear magnetic resonance is applied to monitor the dynamics of the exchanging labile deuterons of polycrystalline L-histidine hydrochloride monohydrate-d7 and α-oxalic acid dihydrate-d6 . Direct experimental evidence of fast dynamics is obtained from T1Z and T1Q measurements. Further motional information is extracted from two-dimensional single-quantum (SQ) and double-quantum (DQ) MAS spectra. Differences between the SQ and DQ linewidths clearly indicate the presence of motions on intermediate timescales for the carboxylic moiety and the D2 O in α-oxalic acid dihydrate, and for the amine group and the D2 O in L-histidine hydrochloride monohydrate. Comparison of the relaxation rate constants of Zeeman and quadrupolar order with the relaxation rate constants of the DQ coherences suggests the co-existence of fast and slow motional processes.

  4. High-resolution proton-detected NMR of proteins at very fast MAS

    NASA Astrophysics Data System (ADS)

    Andreas, Loren B.; Le Marchand, Tanguy; Jaudzems, Kristaps; Pintacuda, Guido

    2015-04-01

    When combined with high-frequency (currently ∼60 kHz) magic-angle spinning (MAS), proton detection boosts sensitivity and increases coherence lifetimes, resulting in narrow 1H lines. Herein, we review methods for efficient proton detected techniques and applications in highly deuterated proteins, with an emphasis on 100% selected 1H site concentration for the purpose of sensitivity. We discuss the factors affecting resolution and sensitivity that have resulted in higher and higher frequency MAS. Next we describe the various methods that have been used for backbone and side-chain assignment with proton detection, highlighting the efficient use of scalar-based 13C-13C transfers. Additionally, we show new spectra making use of these schemes for side-chain assignment of methyl 13C-1H resonances. The rapid acquisition of resolved 2D spectra with proton detection allows efficient measurement of relaxation parameters used as a measure of dynamic processes. Under rapid MAS, relaxation times can be measured in a site-specific manner in medium-sized proteins, enabling the investigation of molecular motions at high resolution. Additionally, we discuss methods for measurement of structural parameters, including measurement of internuclear 1H-1H contacts and the use of paramagnetic effects in the determination of global structure.

  5. High-resolution proton-detected NMR of proteins at very fast MAS.

    PubMed

    Andreas, Loren B; Le Marchand, Tanguy; Jaudzems, Kristaps; Pintacuda, Guido

    2015-04-01

    When combined with high-frequency (currently ∼60 kHz) magic-angle spinning (MAS), proton detection boosts sensitivity and increases coherence lifetimes, resulting in narrow ((1))H lines. Herein, we review methods for efficient proton detected techniques and applications in highly deuterated proteins, with an emphasis on 100% selected ((1))H site concentration for the purpose of sensitivity. We discuss the factors affecting resolution and sensitivity that have resulted in higher and higher frequency MAS. Next we describe the various methods that have been used for backbone and side-chain assignment with proton detection, highlighting the efficient use of scalar-based ((13))C-((13))C transfers. Additionally, we show new spectra making use of these schemes for side-chain assignment of methyl ((13))C-((1))H resonances. The rapid acquisition of resolved 2D spectra with proton detection allows efficient measurement of relaxation parameters used as a measure of dynamic processes. Under rapid MAS, relaxation times can be measured in a site-specific manner in medium-sized proteins, enabling the investigation of molecular motions at high resolution. Additionally, we discuss methods for measurement of structural parameters, including measurement of internuclear ((1))H-((1))H contacts and the use of paramagnetic effects in the determination of global structure.

  6. Magnetic susceptibility effects on 13C MAS NMR spectra of carbon materials and graphite.

    PubMed

    Freita, J C; Emmerich, F G; Cernicchiaro, G R; Sampaio, L C; Bonagamba, T J

    2001-01-01

    13C high-resolution solid-state nuclear magnetic resonance (NMR) was employed to study carbon materials prepared through the thermal decomposition of four different organic precursors (rice hulls, endocarp of babassu coconut, peat, and PVC). For heat treatment temperatures (HTTs) above about 600 C, all materials presented 13C NMR spectra composed of a unique resonance line associated with carbon atoms in aromatic planes. With increasing HTT a continuous broadening of this resonance and a diamagnetic shift in its central frequency were verified for all samples. The evolution of the magnitude and anisotropy of the magnetic susceptibility of the heat-treated carbon samples with HTT explains well these findings. It is shown that these results are better understood when a comparison is made with the features of the 13C NMR spectrum of polycrystalline graphite, for which the magnetic susceptibility effect is also present and is much more pronounced.

  7. Phase Cycling Schemes for finite-pulse-RFDR MAS Solid State NMR Experiments

    PubMed Central

    Zhang, Rongchun; Nishiyama, Yusuke; Sun, Pingchuan; Ramamoorthy, Ayyalusamy

    2015-01-01

    The finite-pulse radio frequency driven dipolar recoupling (fp-RFDR) pulse sequence is used in 2D homonuclear chemical shift correlation experiments under magic angle spinning (MAS). A recent study demonstrated the advantages of using a short phase cycle, XY4, and its super-cycle, XY414, for the fp-RFDR pulse sequence employed in 2D 1H/1H single-quantum/single-quantum correlation experiments under ultrafast MAS conditions. In this study, we report a comprehensive analysis on the dipolar recoupling efficiencies of XY4, XY412, XY413, XY414, and XY814 phase cycles under different spinning speeds ranging from 10 to 100 kHz. The theoretical calculations reveal the presence of second-order terms (T10T2,±2, T1,±1T2,±1, etc.) in the recoupled homonuclear dipolar coupling Hamiltonian only when the basic XY4 phase cycle is utilized, making it advantageous for proton-proton magnetization transfer under ultrafast MAS conditions. It is also found that the recoupling efficiency of fp-RFDR is quite dependent on the duty factor (τ180/τR) as well as on the strength of homonuclear dipolar couplings. The rate of longitudinal magnetization transfer increases linearly with the duty factor of fp-RFDR for all the XY-based phase cycles investigated in this study. Examination of the performances of different phase cycles against chemical shift offset and RF field in homogeneity effects revealed that XY414 is the most tolerant phase cycle, while the shortest phase cycle XY4 suppressed the RF field inhomogeneity effects most efficiently under slow spinning speeds. Our results suggest that the difference in the fp-RFDR recoupling efficiencies decreases with the increasing MAS speed, while ultrafast (>60 kHz) spinning speed is advantageous as it recouples a large amount of homonuclear dipolar couplings and therefore enable fast magnetization exchange. The effects of higher-order terms and cross terms between various interactions in the effective Hamiltonian of fp-RFDR are also analyzed

  8. Phase cycling schemes for finite-pulse-RFDR MAS solid state NMR experiments

    NASA Astrophysics Data System (ADS)

    Zhang, Rongchun; Nishiyama, Yusuke; Sun, Pingchuan; Ramamoorthy, Ayyalusamy

    2015-03-01

    The finite-pulse radio frequency driven dipolar recoupling (fp-RFDR) pulse sequence is used in 2D homonuclear chemical shift correlation experiments under magic angle spinning (MAS). A recent study demonstrated the advantages of using a short phase cycle, XY4, and its super-cycle, XY414, for the fp-RFDR pulse sequence employed in 2D 1H/1H single-quantum/single-quantum correlation experiments under ultrafast MAS conditions. In this study, we report a comprehensive analysis on the dipolar recoupling efficiencies of XY4, XY412, XY413, XY414, and XY814 phase cycles under different spinning speeds ranging from 10 to 100 kHz. The theoretical calculations reveal the presence of second-order terms (T10T2,±2, T1,±1T2,±1, etc.) in the recoupled homonuclear dipolar coupling Hamiltonian only when the basic XY4 phase cycle is utilized, making it advantageous for proton-proton magnetization transfer under ultrafast MAS conditions. It is also found that the recoupling efficiency of fp-RFDR is quite dependent on the duty factor (τ180/τR) as well as on the strength of homonuclear dipolar couplings. The rate of longitudinal magnetization transfer increases linearly with the duty factor of fp-RFDR for all the XY-based phase cycles investigated in this study. Examination of the performances of different phase cycles against chemical shift offset and RF field inhomogeneity effects revealed that XY414 is the most tolerant phase cycle, while the shortest phase cycle XY4 suppressed the RF field inhomogeneity effects most efficiently under slow spinning speeds. Our results suggest that the difference in the fp-RFDR recoupling efficiencies decreases with the increasing MAS speed, while ultrafast (>60 kHz) spinning speed is advantageous as it recouples a large amount of homonuclear dipolar couplings and therefore enable fast magnetization exchange. The effects of higher-order terms and cross terms between various interactions in the effective Hamiltonian of fp-RFDR are also analyzed

  9. Polydisperse methyl β-cyclodextrin–epichlorohydrin polymers: variable contact time 13C CP-MAS solid-state NMR characterization

    PubMed Central

    Mallard, Isabelle; Baudelet, Davy; Castiglione, Franca; Ferro, Monica; Panzeri, Walter; Ragg, Enzio

    2015-01-01

    Summary The polymerization of partially methylated β-cyclodextrin (CRYSMEB) with epichlorohydrin was carried out in the presence of a known amount of toluene as imprinting agent. Three different preparations (D1, D2 and D3) of imprinted polymers were obtained and characterized by solid-state 13C NMR spectroscopy under cross-polarization magic angle spinning (CP-MAS) conditions. The polymers were prepared by using the same synthetic conditions but with different molar ratios of imprinting agent/monomer, leading to morphologically equivalent materials but with different absorption properties. The main purpose of the work was to find a suitable spectroscopic descriptor accounting for the different imprinting process in three homogeneous polymeric networks. The polymers were characterized by studying the kinetics of the cross-polarization process. This approach is based on variable contact time CP-MAS spectra, referred to as VCP-MAS. The analysis of the VCP-MAS spectra provided two relaxation parameters: T CH (the CP time constant) and T 1ρ (the proton spin-lattice relaxation time in the rotating frame). The results and the analysis presented in the paper pointed out that T CH is sensitive to the imprinting process, showing variations related to the toluene/cyclodextrin molar ratio used for the preparation of the materials. Conversely, the observed values of T 1ρ did not show dramatic variations with the imprinting protocol, but rather confirmed that the three polymers are morphologically similar. Thus the combined use of T CH and T 1ρ can be helpful for the characterization and fine tuning of imprinted polymeric matrices. PMID:26877800

  10. Polydisperse methyl β-cyclodextrin-epichlorohydrin polymers: variable contact time (13)C CP-MAS solid-state NMR characterization.

    PubMed

    Mallard, Isabelle; Baudelet, Davy; Castiglione, Franca; Ferro, Monica; Panzeri, Walter; Ragg, Enzio; Mele, Andrea

    2015-01-01

    The polymerization of partially methylated β-cyclodextrin (CRYSMEB) with epichlorohydrin was carried out in the presence of a known amount of toluene as imprinting agent. Three different preparations (D1, D2 and D3) of imprinted polymers were obtained and characterized by solid-state (13)C NMR spectroscopy under cross-polarization magic angle spinning (CP-MAS) conditions. The polymers were prepared by using the same synthetic conditions but with different molar ratios of imprinting agent/monomer, leading to morphologically equivalent materials but with different absorption properties. The main purpose of the work was to find a suitable spectroscopic descriptor accounting for the different imprinting process in three homogeneous polymeric networks. The polymers were characterized by studying the kinetics of the cross-polarization process. This approach is based on variable contact time CP-MAS spectra, referred to as VCP-MAS. The analysis of the VCP-MAS spectra provided two relaxation parameters: T CH (the CP time constant) and T 1ρ (the proton spin-lattice relaxation time in the rotating frame). The results and the analysis presented in the paper pointed out that T CH is sensitive to the imprinting process, showing variations related to the toluene/cyclodextrin molar ratio used for the preparation of the materials. Conversely, the observed values of T 1ρ did not show dramatic variations with the imprinting protocol, but rather confirmed that the three polymers are morphologically similar. Thus the combined use of T CH and T 1ρ can be helpful for the characterization and fine tuning of imprinted polymeric matrices.

  11. High-field 19.6 T 27Al solid-state MAS NMR of in vitro aluminated brain tissue

    NASA Astrophysics Data System (ADS)

    Bryant, Pamela L.; Lukiw, Walter J.; Gan, Zhehong; Hall, Randall W.; Butler, Leslie G.

    2004-10-01

    The combination of 27Al high-field solid-state NMR (19.6 T) with rapid spinning speeds (17.8 kHz) is used to acquire 27Al NMR spectra of total RNA human brain temporal lobe tissues exposed to 0.10 mM Al 3+ (as AlCl 3) and of human retinal pigment epithelial cells (ARPE-19), grown in 0.10 mM AlCl 3. The spectra of these model systems show multiple Al 3+ binding sites, good signal/noise ratios and apparent chemical shift dispersions. A single broad peak (-3 to 11 ppm) is seen for the aluminated ARPE-19 cells, consistent with reported solution-state NMR chemical shifts of Al-transferrin. The aluminated brain tissue has a considerably different 27Al MAS NMR spectrum. In addition to the transferrin-type resonance, additional peaks are seen. Tentative assignments include: -9 to -3 ppm, octahedral AlO 6 (phosphate and water); 9 ppm, condensed AlO 6 units (Al-O-Al bridges); 24 ppm, tetrahedral AlO 3N and/or octahedral Al-carbonate; and 35 ppm, more N-substituted aluminum and /or tetrahedral AlO 4. Thus, brain tissue is susceptible to a broad range of coordination by aluminum. Furthermore, the moderate 27Al C Q values (all less than 10 MHz) suggest future NMR studies may be performed at 9.4 T and a spin rate of 20 kHz.

  12. Incorporation of phosphorus guest ions in the calcium silicate phases of Portland cement from 31P MAS NMR spectroscopy.

    PubMed

    Poulsen, Søren L; Jakobsen, Hans J; Skibsted, Jørgen

    2010-06-21

    Portland cements may contain small quantities of phosphorus (typically below 0.5 wt % P(2)O(5)), originating from either the raw materials or alternative sources of fuel used to heat the cement kilns. This work reports the first (31)P MAS NMR study of anhydrous and hydrated Portland cements that focuses on the phase and site preferences of the (PO(4))(3-) guest ions in the main clinker phases and hydration products. The observed (31)P chemical shifts (10 to -2 ppm), the (31)P chemical shift anisotropy, and the resemblance of the lineshapes in the (31)P and (29)Si MAS NMR spectra strongly suggest that (PO(4))(3-) units are incorporated in the calcium silicate phases, alite (Ca(3)SiO(5)) and belite (Ca(2)SiO(4)), by substitution for (SiO(4))(4-) tetrahedra. This assignment is further supported by a determination of the spin-lattice relaxation times for (31)P in alite and belite, which exhibit the same ratio as observed for the corresponding (29)Si relaxation times. From simulations of the intensities, observed in inversion-recovery spectra for a white Portland cement, it is deduced that 1.3% and 2.1% of the Si sites in alite and belite, respectively, are replaced by phosphorus. Charge balance may potentially be achieved to some extent by a coupled substitution mechanism where Ca(2+) is replaced by Fe(3+) ions, which may account for the interaction of the (31)P spins with paramagnetic Fe(3+) ions as observed for the ordinary Portland cements. A minor fraction of phosphorus may also be present in the separate phase Ca(3)(PO(4))(2), as indicated by the observation of a narrow resonance at delta((31)P) = 3.0 ppm for two of the studied cements. (31)P{(1)H} CP/MAS NMR spectra following the hydration of a white Portland cement show that the resonances from the hydrous phosphate species fall in the same spectral range as observed for (PO(4))(3-) incorporated in alite. This similarity and the absence of a large (31)P chemical shift ansitropy indicate that the hydrous (PO(4

  13. Probing intermolecular interactions in a diethylcarbamazine citrate salt by fast MAS (1)H solid-state NMR spectroscopy and GIPAW calculations.

    PubMed

    Venâncio, Tiago; Oliveira, Lyege Magalhaes; Ellena, Javier; Boechat, Nubia; Brown, Steven P

    2017-03-02

    Fast magic-angle spinning (MAS) NMR is used to probe intermolecular interactions in a diethylcarbamazine salt, that is widely used as a treatment against adult worms of Wuchereria bancrofti which cause a common disease in tropical countries named filariasis. Specifically, a dihydrogen citrate salt that has improved thermal stability and solubility as compared to the free form is studied. One-dimensional (1)H, (13)C and (15)N and two-dimensional (1)H-(13)C and (14)N-(1)H heteronuclear correlation NMR experiments under moderate and fast MAS together with GIPAW (CASTEP) calculations enable the assignment of the (1)H, (13)C and (14)N/(15)N resonances. A two-dimensional (1)H-(1)H double-quantum (DQ) -single-quantum (SQ) MAS spectrum recorded with BaBa recoupling at 60kHz MAS identifies specific proton-proton proximities associated with citrate-citrate and citrate-diethylcarbamazine intermolecular interactions.

  14. Glycerin-Induced Conformational Changes in Bombyx mori Silk Fibroin Film Monitored by 13C CP/MAS NMR and 1H DQMAS NMR

    PubMed Central

    Asakura, Tetsuo; Endo, Masanori; Hirayama, Misaki; Arai, Hiroki; Aoki, Akihiro; Tasei, Yugo

    2016-01-01

    In order to improve the stiff and brittle characteristics of pure Bombyx mori (B. mori) silk fibroin (SF) film in the dry state, glycerin (Glyc) has been used as a plasticizer. However, there have been very limited studies on the structural characterization of the Glyc-blended SF film. In this study, 13C Cross Polarization/Magic Angle Spinning nuclear magnetic resonance (CP/MAS NMR) was used to monitor the conformational changes in the films by changing the Glyc concentration. The presence of only 5 wt % Glyc in the film induced a significant conformational change in SF where Silk I* (repeated type II β-turn and no α-helix) newly appeared. Upon further increase in Glyc concentration, the percentage of Silk I* increased linearly up to 9 wt % Glyc and then tended to be almost constant (30%). This value (30%) was the same as the fraction of Ala residue within the Silk I* form out of all Ala residues of SF present in B. mori mature silkworm. The 1H DQMAS NMR spectra of Glyc-blended SF films confirmed the appearance of Silk I* in the Glyc-blended SF film. A structural model of Glyc-SF complex including the Silk I* form was proposed with the guidance of the Molecular Dynamics (MD) simulation using 1H–1H distance constraints obtained from the 1H Double-Quantum Magic Angle Spinning (DQMAS) NMR spectra. PMID:27618034

  15. 13C MAS NMR studies of the effects of hydration on the cell walls of potatoes and Chinese water chestnuts.

    PubMed

    Tang, H; Belton, P S; Ng, A; Ryden, P

    1999-02-01

    13C NMR with magic angle spinning (MAS) has been employed to investigate the cell walls of potatoes and Chinese water chestnuts over a range of hydration levels. Both single-pulse excitation (SPEMAS) and cross-polarization (CPMAS) experiments were carried out. Hydration led to a substantial increase in signal intensities of galactan and galacturonan in the SPEMAS spectra and a decrease in line width, implying mobilization in the backbone and side chains of pectin. In CPMAS spectra of both samples, noncellulose components showed signal loss as hydration increased. However, the signals of some galacturonan in the 3(1) helix configuration remained in the spectra even when the water content was as high as 110%. Cellulose was unaffected. It is concluded that the pectic polysaccharides experience a distribution of molecular conformations and mobility, whereas cellulose remained as typical rigid solid.

  16. Sensitivity Gains, Linearity, and Spectral Reproducibility in Nonuniformly Sampled Multidimensional MAS NMR Spectra of High Dynamic Range.

    SciTech Connect

    Suiter, Christopher L.; Paramasivam, Sivakumar; Hou, Guangjin; Sun, Shangjin; Rice, David M.; Hoch, Jeffrey C.; Rovnyak, David S.; Polenova, Tatyana E.

    2014-04-22

    Recently, we have demonstrated that considerable inherent sensitivity gains are attained in MAS NMR spectra acquired by nonuniform sampling (NUS) and introduced maximum entropy interpolation (MINT) processing that assures the linearity of transformation between the time and frequency domains. In this report, we examine the utility of the NUS/MINT approach in multidimensional datasets possessing high dynamic range, such as homonuclear 13C–13C correlation spectra. We demonstrate on model compounds and on 1–73-(U-13C,15N)/74–108-(U-15N) E. coli thioredoxin reassembly, that with appropriately constructed 50 % NUS schedules inherent sensitivity gains of 1.7–2.1-fold are readily reached in such datasets. We show that both linearity and line width are retained under these experimental conditions throughout the entire dynamic range of the signals. Furthermore, we demonstrate that the reproducibility of the peak intensities is excellent in the NUS/MINT approach when experiments are repeated multiple times and identical experimental and processing conditions are employed. Finally, we discuss the principles for design and implementation of random exponentially biased NUS sampling schedules for homonuclear 13C–13C MAS correlation experiments that yield high quality artifact-free datasets.

  17. High resolution /sup 10/B and /sup 11/B nuclear magnetic resonance (NMR) spectroscopy of Na/sub 2/B/sub 12/H/sub 11/SH impurities and metabolites

    SciTech Connect

    Samsel, E.G.; Miller, D.L.

    1988-01-01

    High-resolution /l brace//sup 1/H/r brace//sup 10/B and /sup 11/B nuclear magnetic resonance (NMR) has been investigated as a tool for in-vitro examination and analysis of the proposed neutron capture drug, Na/sub 2/B/sub 12/H/sub 11/SH, its impurities, and its metabolites. The instrument used was a 7 T, superconducting IBM NR-300, operating at 96.3 MHz for /sup 11/B and 32.2 MHz for /sup 10/B. High-quality spectra of both nuclei were obtained at concentrations in the 100-500 ppM (boron) range with acquisition periods of minutes to a few hours. A broad background resonance due to borosilicate glass probe components limits the sensitivity of this instrument. Nevertheless, signals for both nuclei were visible in dog blood serum samples at boron concentrations as low as 30 ppM. 2 refs., 1 tab.

  18. Structural investigations of Pu{sup III} phosphate by X-ray diffraction, MAS-NMR and XANES spectroscopy

    SciTech Connect

    Popa, Karin; Raison, Philippe E.; Martel, Laura; Martin, Philippe M.; Solari, Pier L.; Bouëxière, Daniel; Konings, Rudy J.M.; Somers, Joseph

    2015-10-15

    PuPO{sub 4} was prepared by a solid state reaction method and its crystal structure at room temperature was solved by powder X-ray diffraction combined with Rietveld refinement. High resolution XANES measurements confirm the +III valence state of plutonium, in agreement with valence bond derivation. The presence of the americium (as β{sup −} decay product of plutonium) in the +III oxidation state was determined based on XANES spectroscopy. High resolution solid state {sup 31}P NMR agrees with the XANES results and the presence of a solid-solution. - Graphical abstract: A full structural analysis of PuPO{sub 4} based on Rietveld analysis of room temperature X-ray diffraction data, XANES and MAS NMR measurements was performed. - Highlights: • The crystal structure of PuPO{sub 4} monazite is solved. • In PuPO{sub 4} plutonium is strictly trivalent. • The presence of a minute amount of Am{sup III} is highlighted. • We propose PuPO{sub 4} as a potential reference material for spectroscopic and microscopic studies.

  19. The Effect of Antitumor Glycosides on Glioma Cells and Tissues as Studied by Proton HR-MAS NMR Spectroscopy

    PubMed Central

    García-Álvarez, Isabel; Garrido, Leoncio; Romero-Ramírez, Lorenzo; Nieto-Sampedro, Manuel; Fernández-Mayoralas, Alfonso; Campos-Olivas, Ramón

    2013-01-01

    The effect of the treatment with glycolipid derivatives on the metabolic profile of intact glioma cells and tumor tissues, investigated using proton high resolution magic angle spinning (1H HR-MAS) nuclear magnetic resonance (NMR) spectroscopy, is reported here. Two compounds were used, a glycoside and its thioglycoside analogue, both showing anti-proliferative activity on glioma C6 cell cultures; however, only the thioglycoside exhibited antitumor activity in vivo. At the drug concentrations showing anti-proliferative activity in cell culture (20 and 40 µM), significant increases in choline containing metabolites were observed in the 1H NMR spectra of the same intact cells. In vivo experiments in nude mice bearing tumors derived from implanted C6 glioma cells, showed that reduction of tumor volume was associated with significant changes in the metabolic profile of the same intact tumor tissues; and were similar to those observed in cell culture. Specifically, the activity of the compounds is mainly associated with an increase in choline and phosphocholine, in both the cell cultures and tumoral tissues. Taurine, a metabolite that has been considered a biomarker of apoptosis, correlated with the reduction of tumor volume. Thus, the results indicate that the mode of action of the glycoside involves, at least in part, alteration of phospholipid metabolism, resulting in cell death. PMID:24194925

  20. Acetylation of raw cotton for oil spill cleanup application: an FTIR and 13C MAS NMR spectroscopic investigation

    NASA Astrophysics Data System (ADS)

    Adebajo, Moses O.; Frost, Ray L.

    2004-08-01

    Fourier transform infrared (FTIR) and 13C MAS NMR spectroscopy have been used to investigate the acetylation of raw cotton samples with acetic anhydride without solvents in the presence of different amounts of 4-dimethylaminopyridine (DMAP) catalyst. This is a continuation of our previous investigation of acetylation of commercial cotton in an effort to develop hydrophobic, biodegradable, cellulosic sorbent materials for cleaning up oil spills. The FTIR data have again provided a clear evidence for successful acetylation. The NMR results further confirm the successful acetylation. The extent of acetylation was quantitatively determined using the weight percent gain (WPG) due to acetylation and by calculating the ratio R between the intensity of the acetyl CO stretching band at 1740-1745 cm -1 and the intensity of CO stretching vibration of the cellulose backbone at about 1020-1040 cm -1. The FTIR technique was found to be highly sensitive and reliable for the determination of the extent of acetylation. The level of acetylation of the raw cotton samples was found to be much higher than that of cotton fabrics and the previously studied commercial cotton. The variation of the R and WPG with reaction time, amount of DMAP catalyst and different samples of raw cotton is discussed.

  1. Use of SPAM and FAM pulses in high-resolution MAS NMR spectroscopy of quadrupolar nuclei.

    PubMed

    Ball, Thomas J; Wimperis, Stephen

    2007-08-01

    The merits of SPAM and FAM pulses for enhancing the conversion of triple- to single-quantum coherences in the two-dimensional MQMAS experiment are compared using (87)Rb (spin I=3/2) and (27)Al (I=5/2) NMR of crystalline and amorphous materials. Although SPAM pulses are more easily optimized, our experiments and simulations suggest that FAM pulses yield greater signal intensity in all cases. In conclusion, we argue that, as originally suggested, SPAM and FAM pulses are best implemented in phase-modulated whole-echo MQMAS experiments and that the use of SPAM pulses to record separate echo and antiecho data sets, which are then combined, generally yields lower signal-to-noise ratios.

  2. Use of SPAM and FAM pulses in high-resolution MAS NMR spectroscopy of quadrupolar nuclei

    NASA Astrophysics Data System (ADS)

    Ball, Thomas J.; Wimperis, Stephen

    2007-08-01

    The merits of SPAM and FAM pulses for enhancing the conversion of triple- to single-quantum coherences in the two-dimensional MQMAS experiment are compared using 87Rb (spin I = 3/2) and 27Al ( I = 5/2) NMR of crystalline and amorphous materials. Although SPAM pulses are more easily optimized, our experiments and simulations suggest that FAM pulses yield greater signal intensity in all cases. In conclusion, we argue that, as originally suggested, SPAM and FAM pulses are best implemented in phase-modulated whole-echo MQMAS experiments and that the use of SPAM pulses to record separate echo and antiecho data sets, which are then combined, generally yields lower signal-to-noise ratios.

  3. Heteronuclear decoupling in MAS NMR in the intermediate to fast sample spinning regime

    NASA Astrophysics Data System (ADS)

    Equbal, Asif; Bjerring, Morten; Sharma, Kshama; Madhu, P. K.; Nielsen, Niels Chr.

    2016-01-01

    Heteronuclear spin decoupling in solid-state magic-angle spinning NMR is investigated to present methods overcoming interferences between rf irradiation and sample spinning in the intermediate to fast spinning regime. We demonstrate that a recent phase-alternated variant of refocused CW irradiation (rCWApA) provides efficient and robust decoupling in this regime. An extensive experimental and numerical comparison is presented for rCWApA and PISSARRO (phase-inverted supercycled sequence for attenuation of rotary resonance), previously introduced to quench rotary-resonance recoupling effects, under conditions with spinning frequencies between 30 and 60 kHz. Simulations are used to identify the effect of decoupling for various nuclear spin interactions.

  4. Following Solid-Acid-Catalyzed Reactions by MAS NMR Spectroscopy in Liquid Phase -Zeolite-Catalyzed Conversion of Cyclohexanol in Water

    SciTech Connect

    Vjunov, Aleksei; Hu, Mary Y.; Feng, Ju; Camaioni, Donald M.; Mei, Donghai; Hu, Jian Z.; Zhao, Chen; Lercher, Johannes A.

    2014-01-07

    The catalytic conversion of cyclohexanol on zeolite HBEA in hot liquid water leads to dehydration as well as alkylation products. A novel micro autoclave suitable for application in MAS NMR at high temperatures and pressures is developed and successfully applied to obtain new insight into the mechanistic pathway leading to an understanding of the reactions under selected experimental conditions.

  5. Signal intensities in ¹H-¹³C CP and INEPT MAS NMR of liquid crystals.

    PubMed

    Nowacka, A; Bongartz, N A; Ollila, O H S; Nylander, T; Topgaard, D

    2013-05-01

    Spectral editing with CP and INEPT in (13)C MAS NMR enables identification of rigid and mobile molecular segments in concentrated assemblies of surfactants, lipids, and/or proteins. In order to get stricter definitions of the terms "rigid" and "mobile", as well as resolving some ambiguities in the interpretation of CP and INEPT data, we have developed a theoretical model for calculating the CP and INEPT intensities as a function of rotational correlation time τc and C-H bond order parameter SCH, taking the effects of MAS into account. According to the model, the range of τc can at typical experimental settings (5kHz MAS, 1ms ramped CP at 80-100kHz B1 fields) be divided into four regimes: fast (τc<1ns), fast-intermediate (τc≈0.1μs), intermediate (τc≈1μs), and slow (τc>0.1ms). In the fast regime, the CP and INEPT intensities are independent of τc, but strongly dependent on |SCH|, with a cross-over from dominating INEPT to dominating CP at |SCH|>0.1. In the intermediate regime, neither CP nor INEPT yield signal on account of fast T1ρ and T2 relaxation. In both the fast-intermediate and slow regimes, there is exclusively CP signal. The theoretical predictions are tested by experiments on the glass-forming surfactant n-octyl-β-d-maltoside, for which τc can be varied continuously in the nano- to millisecond range by changing the temperature and the hydration level. The atomistic details of the surfactant dynamics are investigated with MD simulations. Based on the theoretical model, we propose a procedure for calculating CP and INEPT intensities directly from MD simulation trajectories. While MD shows that there is a continuous gradient of τc from the surfactant polar headgroup towards the methyl group at the end of the hydrocarbon chain, analysis of the experimental CP and INEPT data indicates that this gradient gets steeper with decreasing temperature and hydration level, eventually spanning four orders of magnitude at completely dry conditions.

  6. Enhanced sensitivity in high-resolution 1H solid-state NMR spectroscopy with DUMBO dipolar decoupling under ultra-fast MAS

    NASA Astrophysics Data System (ADS)

    Salager, Elodie; Stein, Robin S.; Steuernagel, Stefan; Lesage, Anne; Elena, Bénédicte; Emsley, Lyndon

    2009-02-01

    The solid-state NMR 1H homonuclear decoupling sequences in the DUMBO family are shown to be effective at ultra-fast MAS rates of up to 65 kHz. The sequences are applied to model compounds glycine and [2- 13C]- L-alanine as well as the dipeptide β- L-Asp- L-Ala in windowed and continuous phase-modulated versions. They are shown to achieve especially impressive resolution when implemented in a 2D constant-time experiment. At 65 kHz MAS, 1H resolution using homonuclear decoupling is similar to that obtained at lower MAS rates, but peak intensity, and therefore spectral sensitivity, is improved by a factor of 5 over homonuclear-decoupled spectra at 10 kHz MAS.

  7. Hydration properties and phosphorous speciation in native, gelatinized and enzymatically modified potato starch analyzed by solid-state MAS NMR.

    PubMed

    Larsen, Flemming H; Kasprzak, Mirosław M; Lærke, Helle N; Knudsen, Knud Erik B; Pedersen, Sven; Jørgensen, Anne S; Blennow, Andreas

    2013-09-12

    Hydration of granular, gelatinized and molecularly modified states of potato starch in terms of molecular mobility were analyzed by (13)C and (31)P solid-state MAS NMR. Gelatinization (GEL) tremendously reduced the immobile fraction compared to native (NA) starch granules. This effect was enhanced by enzyme-assisted catalytic branching with branching enzyme (BE) or combined BE and β-amylase (BB) catalyzed exo-hydrolysis. Carbons of the glycosidic α-1,6 linkages required high hydration rates before adopting uniform chemical shifts indicating solid-state disorder and poor water accessibility. Comparative analysis of wheat and waxy maize starches demonstrated that starches were similar upon gelatinization independent of botanical origin and that the torsion angles of the glycosidic linkages were averages of the crystalline A and B type structures. In starch suspension phosphorous in immobile regions was only observed in NA starch. Moreover phosphorous was observed in a minor pH-insensitive form and as major phosphate in hydrated GEL and BE starches.

  8. Anisotropic indirect nuclear spin-spin coupling in InP: 31P CP NMR study under slow MAS condition

    NASA Astrophysics Data System (ADS)

    Iijima, Takahiro; Hashi, Kenjiro; Goto, Atsushi; Shimizu, Tadashi; Ohki, Shinobu

    2006-02-01

    The indirect nuclear spin-spin interaction tensor between neighboring 113,115In- 31P spins in Fe-doped InP semiconductor has been studied by 31P NMR spectra measured using CP of 113In → 31P and 115In → 31P under slow MAS condition. The isotropic ( Jiso) and anisotropic ( Janiso = 2/3[ J∥ - J⊥]) parts of the indirect interaction tensor are obtained from the spectral simulation. The acceptable combinations of these values are found to be as follows: ( Jiso, Janiso) = (224 ± 5, 500 ± 100 Hz) or (-224 ± 5, 2100 ± 100 Hz). Although, the coupling constants estimated in this study are slightly different from previously reported values of ∣ Jiso∣ = 350 Hz, Janiso = 1298 Hz [M. Engelsberg, R.E. Norberg, Phys. Rev. B 5 (1972) 3395] and of ∣ Jiso∣ = 225 ± 10, Janiso = (813 ± 50) or (1733 ± 50) Hz [M. Tomaselli et al., Phys. Rev. B 58 (1998) 8627], all of these has the trend that Janiso is rather larger than Jiso.

  9. Solid-state 19F MAS NMR study on the conformation and molecular mobility of poly(chlorotrifluoroethylene).

    PubMed

    Tatsuno, Hiroto; Aimi, Keitaro; Ando, Shinji

    2007-05-01

    The temperature dependence of molecular mobility and conformational changes of poly(chlorotrifluoro- ethylene) (PCTFE) have been investigated by solid-state (19)F magic angle spinning (MAS) NMR spectroscopy. The pulse techniques of dipolar-filter and T(1rho)-filter allow selective observation of the amorphous and crystalline domains, respectively. The temperature dependence of T(1rho) (F) revealed that the segmental motion in the amorphous domain becomes vigorous above ca 80 degrees C, which is well above the glass transition (T(g)) temperature (52 degrees C) and more close to the beta-relaxation temperature (95 degrees C). On the other hand, vigorous molecular motions in the crystalline domain occur above 120 degrees C, which is much below the melting temperature (212 degrees C). This indicates that the polymer chains in the PCTFE crystallites are more mobile than those of typical semicrystalline fluoropolymers like poly(vinylidene fluoride) (PVDF), which can be associated with structural imperfections in the crystallites. In addition, the density functional theory (DFT) calculations of (19)F magnetic shielding suggest that the high-frequency shifts observed for the crystalline signals above 80 degrees C can be ascribed to the conformational change around meso diads toward more twisted and/or helical conformations in the main chain.

  10. LC/ESI-MS n and 1H HR-MAS NMR analytical methods as useful taxonomical tools within the genus Cystoseira C. Agardh (Fucales; Phaeophyceae).

    PubMed

    Jégou, Camille; Culioli, Gérald; Kervarec, Nelly; Simon, Gaëlle; Stiger-Pouvreau, Valérie

    2010-12-15

    Species of the genus Cystoseira are particularly hard to discriminate, due to the complexity of their morphology, which can be influenced by their phenological state and ecological parameters. Our study emphasized on the relevance of two kinds of analytical tools, (1) LC/ESI-MS(n) and (2) (1)H HR-MAS NMR, also called in vivo NMR, to identify Cystoseira specimens at the specific level and discuss their taxonomy. For these analyses, samples were collected at several locations in Brittany (France), where Cystoseira baccata, C. foeniculacea, C. humilis, C. nodicaulis and C. tamariscifolia were previously reported. To validate our chemical procedure, the sequence of the ITS2 has been obtained for each species to investigate their phylogenetic relationships at a molecular level. Our study highlighted the consistency of the two physico-chemical methods, compared to "classical" molecular approach, in studying taxonomy within the genus Cystoseira. Especially, LC/ESI-MS(n) and phylogenetic analyses converged into the discrimination of two taxonomical groups among the 5 species. The occurrence of some specific signals in the (1)H HR-MAS NMR spectra and/or some characteristic chemical compounds during LC/ESI-MS(n) analysis could be regarded as discriminating factors. LC/ESI-MS(n) and (1)H HR-MAS NMR turned out to be two relevant and innovative techniques to discriminate taxonomically this complex genus.

  11. Line shapes and widths of MAS sidebands for 27Al satellite transitions. multinuclear MAS NMR of tugtupite Na8Al2Be2Si8O24Cl2.

    PubMed

    Skibsted, J; Norby, P; Bildsøe, H; Jakobsen, H J

    1995-12-01

    A multinuclear 9Be, 23Na, 27Al, and 29Si magic-angle spinning (MAS) NMR study has been performed for the mineral tugtupite (Na8Al2Be2Si8O24Cl2). The extremely well-resolved spectra allow observation of separate spinning sidebands (ssb's) from the inner (+/- 1/2, +/- 3/2) and outer (+/- 3/2, +/- 5/2) 27Al satellite transitions, and are utilized in a detailed analysis of the line shapes and widths of the individual ssb's from simulations. The line widths of the ssb's from the inner and outer 27Al satellite transitions are found to decrease systematically with increasing order of the ssb's across the spectrum. Accurate values for the 9Be, 23Na, and 27Al quadrupole coupling parameters and isotropic chemical shifts are obtained from simulations of the manifolds of ssb's from the satellite transitions. MAS NMR of the 9Be satellite transitions for tugtupite, BeO, and beryl(Al2Be3Si6O18) shows that these transitions are particularly useful for determination of 9Be quadrupole couplings because of the small 9Be quadrupole moment. The 29Si shielding anisotropy of delta sigma = 48 ppm in tugtupite is the largest determined so far for a framework SiO4 tetrahedron. Finally, the crystal structure of the tugtupite sample has been refined by single-crystal X-ray diffraction, and correlations between the multinuclear NMR parameters and structural data are reported.

  12. Identification of Li-Ion Battery SEI Compounds through (7)Li and (13)C Solid-State MAS NMR Spectroscopy and MALDI-TOF Mass Spectrometry.

    PubMed

    Huff, Laura A; Tavassol, Hadi; Esbenshade, Jennifer L; Xing, Wenting; Chiang, Yet-Ming; Gewirth, Andrew A

    2016-01-13

    Solid-state (7)Li and (13)C MAS NMR spectra of cycled graphitic Li-ion anodes demonstrate SEI compound formation upon lithiation that is followed by changes in the SEI upon delithiation. Solid-state (13)C DPMAS NMR shows changes in peaks associated with organic solvent compounds (ethylene carbonate and dimethyl carbonate, EC/DMC) upon electrochemical cycling due to the formation of and subsequent changes in the SEI compounds. Solid-state (13)C NMR spin-lattice (T1) relaxation time measurements of lithiated Li-ion anodes and reference poly(ethylene oxide) (PEO) powders, along with MALDI-TOF mass spectrometry results, indicate that large-molecular-weight polymers are formed in the SEI layers of the discharged anodes. MALDI-TOF MS and NMR spectroscopy results additionally indicate that delithiated anodes exhibit a larger number of SEI products than is found in lithiated anodes.

  13. Optimum levels of exchangeable protons in perdeuterated proteins for proton detection in MAS solid-state NMR spectroscopy.

    PubMed

    Akbey, Umit; Lange, Sascha; Trent Franks, W; Linser, Rasmus; Rehbein, Kristina; Diehl, Anne; van Rossum, Barth-Jan; Reif, Bernd; Oschkinat, Hartmut

    2010-01-01

    We present a systematic study of the effect of the level of exchangeable protons on the observed amide proton linewidth obtained in perdeuterated proteins. Decreasing the amount of D(2)O employed in the crystallization buffer from 90 to 0%, we observe a fourfold increase in linewidth for both (1)H and (15)N resonances. At the same time, we find a gradual increase in the signal-to-noise ratio (SNR) for (1)H-(15)N correlations in dipolar coupling based experiments for H(2)O concentrations of up to 40%. Beyond 40%, a significant reduction in SNR is observed. Scalar-coupling based (1)H-(15)N correlation experiments yield a nearly constant SNR for samples prepared with < or =30% H(2)O. Samples in which more H(2)O is employed for crystallization show a significantly reduced NMR intensity. Calculation of the SNR by taking into account the reduction in (1)H T (1) in samples containing more protons (SNR per unit time), yields a maximum SNR for samples crystallized using 30 and 40% H(2)O for scalar and dipolar coupling based experiments, respectively. A sensitivity gain of 3.8 is obtained by increasing the H(2)O concentration from 10 to 40% in the CP based experiment, whereas the linewidth only becomes 1.5 times broader. In general, we find that CP is more favorable compared to INEPT based transfer when the number of possible (1)H,(1)H interactions increases. At low levels of deuteration (> or =60% H(2)O in the crystallization buffer), resonances from rigid residues are broadened beyond detection. All experiments are carried out at MAS frequency of 24 kHz employing perdeuterated samples of the chicken alpha-spectrin SH3 domain.

  14. The metabolic profile of lemon juice by proton HR-MAS NMR: the case of the PGI Interdonato Lemon of Messina.

    PubMed

    Cicero, Nicola; Corsaro, Carmelo; Salvo, Andrea; Vasi, Sebastiano; Giofré, Salvatore V; Ferrantelli, Vincenzo; Di Stefano, Vita; Mallamace, Domenico; Dugo, Giacomo

    2015-01-01

    We have studied by means of High Resolution Magic Angle Spinning Nuclear Magnetic Resonance (HR-MAS NMR) the metabolic profile of the famous Sicilian lemon known as 'Interdonato Lemon of Messina PGI'. The PGI Interdonato Lemon of Messina possesses high organoleptic and healthy properties and is recognised as one of the most nutrient fruits. In particular, some of its constituents are actively studied for their chemo-preventive and therapeutic properties. In this paper, we have determined by means of HR-MAS NMR spectroscopy the molar concentration of the main metabolites constituent the juice of PGI Interdonato Lemon of Messina in comparison with that of the not-PGI Interdonato Lemon of Turkey. Our aim is to develop an analytical technique, in order to determine a metabolic fingerprint able to reveal commercial frauds in national and international markets.

  15. Nanoscopic yttrium oxide fluorides: non-aqueous fluorolytic sol-gel synthesis and structural insights by 19F and 89Y MAS NMR.

    PubMed

    Scholz, G; Dreger, M; Bertram, R; Kemnitz, E

    2015-08-14

    Nanoscopic yttrium acetate fluorides Y(CH(3)COO)(3-z)F(z) and yttrium oxide fluorides YO(3-z)/(2)F(z )were prepared with tunable Y/F molar ratios via the fluorolytic sol-gel route. All samples were characterized by X-ray diffraction, elemental analysis and thermal analysis. In addition, local structures of all samples were studied by (19)F MAS, (19)F-(89)Y CP MAS and (1)H-(89)Y CP MAS NMR spectroscopy and the respective chemical shifts are given. For both classes of compounds, only the fluorination using one equivalent of F (z = 1) leads to defined, well crystalline matrices: yttrium acetate fluoride Y(CH(3)COO)(2)F and r-YOF.

  16. Fine-tuned characterization at the solid/solution interface of organotin compounds grafted onto cross-linked polystyrene by using high-resolution MAS NMR spectroscopy.

    PubMed

    Martins, José C; Mercier, Frédéric A G; Vandervelden, Alexander; Biesemans, Monique; Wieruszeski, Jean-Michel; Humpfer, Eberhard; Willem, Rudolph; Lippens, Guy

    2002-08-02

    The structural characterization of organotin compounds that are grafted onto insoluble cross-linked polymers has necessarily been limited to elemental analysis, infrared spectroscopy, and in a few instances, solid-state NMR spectroscopy. This important bottleneck in the development of such grafted systems has been addressed by using high-resolution magic angle spinning (hr-MAS) NMR spectroscopy. The great potential of this technique is demonstrated through the structural characterization of diphenylbutyl-(3,4) and dichlorobutylstannanes (5,6), grafted onto divinylbenzene cross-linked polystyrene by means of a suitable linker (1, 2). First, conditions suitable for the application of hr-MAS NMR spectroscopy were identified by characterizing the (1)H resonance line widths of the grafted organotin moiety following swelling of the functionalized beads in eight representative solvents. The presence of clearly identifiable tin coupling patterns in both the 1D (13)C and 2D (1)H-(13)C HSQC spectra, and the incorporation of (119)Sn chemical shift and connectivity information from hr-MAS 1D (119)Sn and 2D (1)H-(119)Sn HMQC spectra, provide an unprecedented level of characterization of grafted organotins directly at the solid/liquid interface. In addition, the use of hr-MAS (119)Sn NMR for reaction monitoring, impurity detection, and quantification and assessment of the extent of coordination reveals its promise as a novel tool for the investigation of polymer-grafted organotin compounds. The approach described here should be sufficiently general for extension to a variety of other nuclei of interest in polymer-supported organometallic chemistry.

  17. Insight into hydrogen bonding of uranyl hydroxide layers and capsules by use of 1H magic-angle spinning NMR spectroscopy [Insight into the hydrogen bonding for uranyl hydroxides using 1H MAS NMR spectroscopy

    DOE PAGES

    Alam, Todd M.; Liao, Zuolei; Nyman, May; ...

    2016-04-27

    Solid-state 1H magic-angle spinning (MAS) NMR was used to investigate local proton environments in anhydrous [UO2(OH)2] (α-UOH) and hydrated uranyl hydroxide [(UO2)4O(OH)6·5H2O (metaschoepite). For the metaschoepite material, proton resonances of the μ2-OH hydroxyl and interlayer waters were resolved, with two-dimensional (2D) double-quantum (DQ) 1H–1H NMR correlation experiments revealing strong dipolar interactions between these different proton species. The experimental NMR results were combined with first-principles CASTEP GIPAW (gauge including projector-augmented wave) chemical shift calculations to develop correlations between hydrogen-bond strength and observed 1H NMR chemical shifts. Furthermore, these NMR correlations allowed characterization of local hydrogen-bond environments in uranyl U24 capsules andmore » of changes in hydrogen bonding that occurred during thermal dehydration of metaschoepite.« less

  18. Investigation of cation environment and framework changes in silicotitanate exchange materials using solid-state 23Na, 29Si, and 133Cs MAS NMR

    NASA Astrophysics Data System (ADS)

    Cherry, Brian R.; Nyman, May; Alam, Todd M.

    2004-06-01

    Crystalline silicotitanate (CST), HNa 3Ti 4Si 2O 14·4H 2O and the Nb-substituted CST (Nb-CST), HNa 2Ti 3NbSi 2O 14·4H 2O, are highly selective Cs + sorbents, which makes them attractive materials for the selective removal of radioactive species from nuclear waste solutions. The structural basis for the improved Cs + selectivity in the niobium analogs was investigated through a series of solid-state magic angle spinning (MAS) NMR experiments. Changes in the local environment of the Na + and Cs + cations in both CST and Nb-CST materials as a function of weight percent cesium exchange were investigated using 23Na and 133Cs MAS NMR. Framework changes induced by Cs + loading and hydration state were investigated with 29Si MAS NMR. Multiple Cs + environments were observed in the CST and Nb-CST material. The relative population of these different Cs + environments varies with the extent of Cs + loading. Marked changes in the framework Si environment were noted with the initial incorporation of Cs +, however with increased Cs + loading the impact to the Si environment becomes less pronounced. The Cs + environment and Si framework structure were influenced by the Nb-substitution and were greatly affected by the amount of water present in the materials. The increased Cs + selectivity of the Nb-CST materials arises from both the chemistry and geometry of the tunnels and pores.

  19. A spectrometer designed for 6.7 and 14.1 T DNP-enhanced solid-state MAS NMR using quasi-optical microwave transmission

    NASA Astrophysics Data System (ADS)

    Pike, Kevin J.; Kemp, Thomas F.; Takahashi, Hiroki; Day, Robert; Howes, Andrew P.; Kryukov, Eugeny V.; MacDonald, James F.; Collis, Alana E. C.; Bolton, David R.; Wylde, Richard J.; Orwick, Marcella; Kosuga, Kosuke; Clark, Andrew J.; Idehara, Toshitaka; Watts, Anthony; Smith, Graham M.; Newton, Mark E.; Dupree, Ray; Smith, Mark E.

    2012-02-01

    A Dynamic Nuclear Polarisation (DNP) enhanced solid-state Magic Angle Spinning (MAS) NMR spectrometer operating at 6.7 T is described and demonstrated. The 187 GHz TE13 fundamental mode of the FU CW VII gyrotron is used as the microwave source for this magnetic field strength and 284 MHz 1H DNP-NMR. The spectrometer is designed for use with microwave frequencies up to 395 GHz (the TE16 second-harmonic mode of the gyrotron) for DNP at 14.1 T (600 MHz 1H NMR). The pulsed microwave output from the gyrotron is converted to a quasi-optical Gaussian beam using a Vlasov antenna and transmitted to the NMR probe via an optical bench, with beam splitters for monitoring and adjusting the microwave power, a ferrite rotator to isolate the gyrotron from the reflected power and a Martin-Puplett interferometer for adjusting the polarisation. The Gaussian beam is reflected by curved mirrors inside the DNP-MAS-NMR probe to be incident at the sample along the MAS rotation axis. The beam is focussed to a ˜1 mm waist at the top of the rotor and then gradually diverges to give much more efficient coupling throughout the sample than designs using direct waveguide irradiation. The probe can be used in triple channel HXY mode for 600 MHz 1H and double channel HX mode for 284 MHz 1H, with MAS sample temperatures ⩾85 K. Initial data at 6.7 T and ˜1 W pulsed microwave power are presented with 13C enhancements of 60 for a frozen urea solution (1H-13C CP), 16 for bacteriorhodopsin in purple membrane (1H-13C CP) and 22 for 15N in a frozen glycine solution (1H-15N CP) being obtained. In comparison with designs which irradiate perpendicular to the rotation axis the approach used here provides a highly efficient use of the incident microwave beam and an NMR-optimised coil design.

  20. A spectrometer designed for 6.7 and 14.1 T DNP-enhanced solid-state MAS NMR using quasi-optical microwave transmission.

    PubMed

    Pike, Kevin J; Kemp, Thomas F; Takahashi, Hiroki; Day, Robert; Howes, Andrew P; Kryukov, Eugeny V; MacDonald, James F; Collis, Alana E C; Bolton, David R; Wylde, Richard J; Orwick, Marcella; Kosuga, Kosuke; Clark, Andrew J; Idehara, Toshitaka; Watts, Anthony; Smith, Graham M; Newton, Mark E; Dupree, Ray; Smith, Mark E

    2012-02-01

    A Dynamic Nuclear Polarisation (DNP) enhanced solid-state Magic Angle Spinning (MAS) NMR spectrometer operating at 6.7 T is described and demonstrated. The 187 GHz TE(13) fundamental mode of the FU CW VII gyrotron is used as the microwave source for this magnetic field strength and 284 MHz (1)H DNP-NMR. The spectrometer is designed for use with microwave frequencies up to 395 GHz (the TE(16) second-harmonic mode of the gyrotron) for DNP at 14.1T (600 MHz (1)H NMR). The pulsed microwave output from the gyrotron is converted to a quasi-optical Gaussian beam using a Vlasov antenna and transmitted to the NMR probe via an optical bench, with beam splitters for monitoring and adjusting the microwave power, a ferrite rotator to isolate the gyrotron from the reflected power and a Martin-Puplett interferometer for adjusting the polarisation. The Gaussian beam is reflected by curved mirrors inside the DNP-MAS-NMR probe to be incident at the sample along the MAS rotation axis. The beam is focussed to a ~1 mm waist at the top of the rotor and then gradually diverges to give much more efficient coupling throughout the sample than designs using direct waveguide irradiation. The probe can be used in triple channel HXY mode for 600 MHz (1)H and double channel HX mode for 284 MHz (1)H, with MAS sample temperatures ≥85 K. Initial data at 6.7 T and ~1 W pulsed microwave power are presented with (13)C enhancements of 60 for a frozen urea solution ((1)H-(13)C CP), 16 for bacteriorhodopsin in purple membrane ((1)H-(13)C CP) and 22 for (15)N in a frozen glycine solution ((1)H-(15)N CP) being obtained. In comparison with designs which irradiate perpendicular to the rotation axis the approach used here provides a highly efficient use of the incident microwave beam and an NMR-optimised coil design.

  1. High field 27Al MAS NMR and TPD studies of active sites in ethanol dehydration using thermally treated transitional aluminas as catalysts

    SciTech Connect

    Hu, Jian Zhi; Xu, Suochang; Kwak, Ja Hun; Hu, Mary Y.; Wan, Chuan; Zhao, Zhenchao; Szanyi, Janos; Bao, Xinhe; Han, Xiuwen; Wang, Yong; Peden, Charles H. F.

    2016-04-01

    Gamma-, sigma- and theta-Al2O3 are well known metastable “transitional” alumina structural polymorphs. Upon heating, Al2O3 transitions to the so-called and Al2O3 polymorphs and finally forms the thermally stable Al2O3. The poorly developed crystallinity and co-existence of the , , and Al2O3 prior to forming all Al2O3, making it difficult to characterize the structures as well as to quantify the various phases of the transition alumina. As a result, there are significant controversies in the literatures. In this work, a detailed NMR analysis was carried out at high magnetic field on three special aluminum oxide samples where the, , , Al2O3 phases are made dominant, respectively, by controlling the synthesis conditions. The goal is to simplify, including making unambiguous, spectral assignments in 27Al MAS NMR spectra of transition alumina that have not yet been commonly agreed previously. Specifically, quantitative 1D 27Al MAS NMR was used to quantify the ratios of the different alumina structural units, 2D MQMAS 27Al MAS was used for obtaining the highest spectral resolution to guide the analysis of the 1D spectrum, and a saturation pulse sequence was integrated into the 1D NMR to select the amorphous structures, including obtain spectra where the penta-coordinate sites are observed with enhanced relative intensity. Collectively, this study uniquely assigns Al-peaks (both octahedral and tetrahedral) to the Al2O3 and the Al2O3 phases and offers a new way of understanding, including quantifying, the different structural units and sites in transition alumina samples.

  2. Solid state structure by X-ray and 13C CP/MAS NMR of new 5-[2-(N,N-dimethylamino)ethoxy]-4,7-dimethylcoumarins

    NASA Astrophysics Data System (ADS)

    Ostrowska, Kinga; Maciejewska, Dorota; Dobrzycki, Łukasz; Socha, Pawel

    2016-05-01

    5-[2-(N,N-dimethylamino)ethoxy]-4,7-dimethylcoumarin (1) and 6-acetyl-5-[2-(N,N-dimethylamino)ethoxy]-4,7-dimethylcoumarin (2), structurally related, were synthesized using both conventional and microwave-assisted approach. An impact of acetyl groups on the molecular structure of coumarin derivatives has been examined. Crystals of 2 were investigated using single crystal and powder X-ray diffraction techniques. Compound 2 crystallizes forming two polymorphs (denoted as 2_1 and 2_2), both belonging to P21/c space group. Both polymorphs are comparably stable and can be formed simultaneously during crystallization process. The solid state structure was also analysed using the fully resolved 13C CP/MAS NMR. The double signals with the intensity ratio of about 1:1 which were observed in the 13C CP/MAS NMR spectrum of compound 1 must arise due to the presence of two conformers of 1. In contrast, NMR spectrum recorded for powder mixture of two polymorphs of compound 2 displays no signal splitting. This is related to structural similarities of molecules in both polymorphs.

  3. FTIR and 1H MAS NMR investigations on the correlation between the frequency of stretching vibration and the chemical shift of surface OH groups of solids

    NASA Astrophysics Data System (ADS)

    Brunner, Eike; Karge, H. G.; Pfeifer, H.

    1992-03-01

    The study of surface hydroxyl groups of solids, especially of zeolites, belongs to the 'classical' topics of IR spectroscopy since physico-chemical information may be derived from the wavenumber (nu) OH of the stretching vibration of the different hydroxyls. On the other hand, the last decade has seen the development of high resolution solid-state NMR spectroscopy and through the use of the so-called magic-angle-spinning technique (MAS) the signals of different hydroxyl species can be resolved in the 1H NMR spectra of solids. The chemical shift (delta) H describing the position of these lines may be used as well as (nu) OH to characterize quantitatively the strength of acidity of surface OH groups of solids. In a first comparison of (nu) OH with (delta) H for several types of surface OH groups, a linear correlation between them could be found. The aim of this paper was to prove the validity of this correlation for a wide variety of hydroxyls. The IR measurements were carried out on a Perkin-Elmer FTIR spectrometer 1800 at the Fritz Haber Institute of the Max Planck Society, Berlin, and the 1H MAS NMR spectra were recorded on a Bruker MSL- 300 at the University of Leipzig.

  4. The combined use of quantum chemical calculations and CP/MAS NMR spectroscopy to investigate soil bound residues of labeled xenobiotics

    NASA Astrophysics Data System (ADS)

    Lewandowski, Hans; Philipp, Herbert; Meier, Robert J.; Narres, Hans-Dieter; Berns, Anne E.

    2010-05-01

    Application of solid state Nuclear Magnetic Resonance (NMR) spectroscopy to 13C- and 15N-labeled compounds is a powerful tool to study the interactions of xenobiotics with soil and its components. The type of interaction with soil components, like organic matter or the mineral phase, influences binding and release of a xenobiotic and its metabolites in soil. As such interactions to the soil matrix cause shifts in the initial positions of the NMR signals of the investigated labeled compound, NMR can be used to elucidate the binding type of bound residues. Density functional theory (DFT) calculations are excellent suited to support such NMR studies of xenobiotics. In a first step, DFT calculations were used to support the interpretation of the spectra of labeled xenobiotics, their metabolites and reaction products synthesized through reaction with model substances (representing specific functionalities of humic substances). In a second step, they allow to evaluate the influence of possible bonds on the initial chemical shift (e.g. towards higher or lower field). This can be especially helpful in the case of bonds like van-der-Waals interactions, for which it is difficult to prepare defined model substances. CP/MAS-NMR spectroscopy and DFT calculations were applied to study the interactions of several labeled xenobiotics and soil organic matter.

  5. Structure, Vibrational Spectra and (11)B-NMR Chemical Shift of Na8[AlSiO4]6(B(OH)4)2: Comparison of Theory and Experiment.

    PubMed

    Schneider, Alexander G; Schomborg, Lars; Ulpe, Anna C; Rüscher, Claus H; Bredow, Thomas

    2016-09-29

    Density functional theory (DFT) calculations at generalized gradient approximation (GGA) level were performed to interpret experimental IR and Raman vibrational spectra, to assign (11)B-NMR chemical shifts, and to calculate the structure of the tetrahydroxyborate sodalite Na8[AlSiO4]6(B(OH)4)2. Full optimization of the intercalated compound gave the following structural parameters of B(OH)4(-): B-O-B (105.3-115.3°) and B-O-H (111.5-115.4°) angles, B-O (1.476 Å, 1.491 Å) and O-H (0.98 Å) distances. The calculated normal modes were assigned to experimental IR and Raman spectra. In general, close agreement between theory and experiment was obtained. The mean absolute deviation (MAD) is below 11 cm(-1). We also calculate the thermodynamical stability of Na8[AlSiO4]6(B(OH)4)2 with respect to Na8[AlSiO4]6(BH4)2 in the context of the tetrahydroborate hydration reaction.

  6. Satellite transitions acquired in real time by magic angle spinning (STARTMAS): ``Ultrafast'' high-resolution MAS NMR spectroscopy of spin I =3/2 nuclei

    NASA Astrophysics Data System (ADS)

    Thrippleton, Michael J.; Ball, Thomas J.; Wimperis, Stephen

    2008-01-01

    The satellite transitions acquired in real time by magic angle spinning (STARTMAS) NMR experiment combines a train of pulses with sample rotation at the magic angle to refocus the first- and second-order quadrupolar broadening of spin I =3/2 nuclei in a series of echoes, while allowing the isotropic chemical and quadrupolar shifts to evolve. The result is real-time isotropic NMR spectra at high spinning rates using conventional MAS equipment. In this paper we describe in detail how STARTMAS data can be acquired and processed with ease on commercial equipment. We also discuss the advantages and limitations of the approach and illustrate the discussion with numerical simulations and experimental data from four different powdered solids.

  7. High field 27Al MAS NMR and TPD studies of active sites in ethanol dehydration using thermally treated transitional aluminas as catalysts

    SciTech Connect

    Hu, Jian Zhi; Xu, Suochang; Kwak, Ja Hun; Hu, Mary Y.; Wan, Chuan; Zhao, Zhenchao; Szanyi, Janos; Bao, Xinhe; Han, Xiuwen; Wang, Yong; Peden, Charles H. F.

    2016-04-01

    High field quantitative 27Al MAS NMR and temperature programmed desorption (TPD) of ethanol are used to study the surface and phase transformation of gamma-Al2O3 during calcination in the temperature range of 500 to 1300 degrees C. Following ethanol adsorption, ethylene is generated during TPD with a desorption temperature > 200 degrees C. With increasing calcination temperature prior to TPD, the amount of ethylene produced decreases monotonically. Significantly, 27Al MAS NMR reveals that the amount of penta-coordinate Al3+ ions (Lewis acid sites) also decreases with increasing calcination temperature. In fact, a strong correlation between the amount of penta-coordinate Al3+ ions and the amount of strongly adsorbed ethanol molecules (i.e., the ones that convert to ethylene during TPD) is obtained. This result indicates that the penta-coordinate aluminum sites are the catalytic active sites on alumina surfaces during ethanol dehydration reaction across the entire course of gamma- to alpha-Al2O3 phase transformations.

  8. Solid state {sup 31}P/{sup 27}Al and {sup 31}P/{sup 23}Na MAS NMR dipolar dephasing investigations of connectivity in sodium aluminophosphate glasses

    SciTech Connect

    LANG,DAVID P.; ALAM,TODD M.; BENCOE,DENISE N.

    2000-05-01

    Solid state {sup 31}P/{sup 27}Al and {sup 31}P/{sup 23}Na MAS NMR dipolar dephasing experiments have been used to investigate the spatial distribution of aluminum and sodium cations with respect to the phosphate backbone for a series of sodium aluminophosphate glasses, xAl{sub 2}O{sub 3}{center_dot}50Na{sub 2}O{center_dot}(50{minus}x)P{sub 2}O{sub 5} (0{le} x {le} 17.5). From the {sup 31}P/{sup 27}Al and {sup 31}P/{sup 23}Na connectivity data gathered, information about the medium range order in these glasses is obtained. The expanded connectivity data allows for better identification and interpretation of the new resonances observed in the {sup 31}P MAS NMR spectra with the addition of alumina. The results of the dipolar dephasing experiments show that the sodium-phosphate distribution remains relatively unchanged for the glass series, and that the addition of aluminum occurs primarily through the depolymerization of the phosphate tetrahedral backbone.

  9. Separation of small metabolites and lipids in spectra from biopsies by diffusion-weighted HR-MAS NMR: a feasibility study.

    PubMed

    Diserens, G; Vermathen, M; Precht, C; Broskey, N T; Boesch, C; Amati, F; Dufour, J-F; Vermathen, P

    2015-01-07

    High Resolution Magic Angle Spinning (HR-MAS) NMR allows metabolic characterization of biopsies. HR-MAS spectra from tissues of most organs show strong lipid contributions that are overlapping metabolite regions, which hamper metabolite estimation. Metabolite quantification and analysis would benefit from a separation of lipids and small metabolites. Generally, a relaxation filter is used to reduce lipid contributions. However, the strong relaxation filter required to eliminate most of the lipids also reduces the signals for small metabolites. The aim of our study was therefore to investigate different diffusion editing techniques in order to employ diffusion differences for separating lipid and small metabolite contributions in the spectra from different organs for unbiased metabonomic analysis. Thus, 1D and 2D diffusion measurements were performed, and pure lipid spectra that were obtained at strong diffusion weighting (DW) were subtracted from those obtained at low DW, which include both small metabolites and lipids. This subtraction yielded almost lipid free small metabolite spectra from muscle tissue. Further improved separation was obtained by combining a 1D diffusion sequence with a T2-filter, with the subtraction method eliminating residual lipids from the spectra. Similar results obtained for biopsies of different organs suggest that this method is applicable in various tissue types. The elimination of lipids from HR-MAS spectra and the resulting less biased assessment of small metabolites have potential to remove ambiguities in the interpretation of metabonomic results. This is demonstrated in a reproducibility study on biopsies from human muscle.

  10. Low-power broadband homonuclear dipolar recoupling in MAS NMR by two-fold symmetry pulse schemes for magnetization transfers and double-quantum excitation

    NASA Astrophysics Data System (ADS)

    Teymoori, Gholamhasan; Pahari, Bholanath; Edén, Mattias

    2015-12-01

    We provide an experimental, numerical, and high-order average Hamiltonian evaluation of an open-ended series of homonuclear dipolar recoupling sequences, SR2 2p 1 with p = 1, 2, 3, … . While operating at a very low radio-frequency (rf) power, corresponding to a nutation frequency of 1/2 of the magic-angle spinning (MAS) rate (ωnut =ωr / 2), these recursively generated double-quantum (2Q) dipolar recoupling schemes offer a progressively improved compensation to resonance offsets and rf inhomogeneity for increasing pulse-sequence order p. The excellent recoupling robustness to these experimental obstacles, as well as to CSA, is demonstrated for 2Q filtering (2QF) experiments and for driving magnetization transfers in 2D NMR correlation spectroscopy, where the sequences may provide either double or zero quantum dipolar Hamiltonians during mixing. Experimental and numerical demonstrations, which mostly target conditions of "ultra-fast" MAS (≳50 kHz) and high magnetic fields, are provided for recoupling of 13C across a wide range of isotropic and anisotropic chemical shifts, as well as dipolar coupling constants, encompassing [2,3-13C2 ]alanine, [1,3-13C2 ]alanine, diammonium [1,4-13C2 ]fumarate, and [U-13 C]tyrosine. When compared at equal power levels, a superior performance is observed for the SR2p 1 sequences with p ⩾ 3 relative to existing and well-established 2Q recoupling techniques. At ultra-fast MAS, proton decoupling is redundant during the homonuclear dipolar recoupling of dilute spins in organic solids, which renders the family of SR2p 1 schemes the first efficient 2Q recoupling option for general applications, such as 2Q-1Q correlation NMR and high-order multiple-quantum excitation, under truly low-power rf conditions.

  11. Low-power broadband homonuclear dipolar recoupling in MAS NMR by two-fold symmetry pulse schemes for magnetization transfers and double-quantum excitation.

    PubMed

    Teymoori, Gholamhasan; Pahari, Bholanath; Edén, Mattias

    2015-12-01

    We provide an experimental, numerical, and high-order average Hamiltonian evaluation of an open-ended series of homonuclear dipolar recoupling sequences, SR [Formula: see text] with p=1,2,3,…. While operating at a very low radio-frequency (rf) power, corresponding to a nutation frequency of 1/2 of the magic-angle spinning (MAS) rate (ωnut=ωr/2), these recursively generated double-quantum (2Q) dipolar recoupling schemes offer a progressively improved compensation to resonance offsets and rf inhomogeneity for increasing pulse-sequence order p. The excellent recoupling robustness to these experimental obstacles, as well as to CSA, is demonstrated for 2Q filtering (2QF) experiments and for driving magnetization transfers in 2D NMR correlation spectroscopy, where the sequences may provide either double or zero quantum dipolar Hamiltonians during mixing. Experimental and numerical demonstrations, which mostly target conditions of "ultra-fast" MAS (≳50kHz) and high magnetic fields, are provided for recoupling of (13)C across a wide range of isotropic and anisotropic chemical shifts, as well as dipolar coupling constants, encompassing [2,3-(13)C2]alanine, [1,3-(13)C2]alanine, diammonium [1,4-(13)C2]fumarate, and [U-(13)C]tyrosine. When compared at equal power levels, a superior performance is observed for the SR [Formula: see text] sequences with p⩾3 relative to existing and well-established 2Q recoupling techniques. At ultra-fast MAS, proton decoupling is redundant during the homonuclear dipolar recoupling of dilute spins in organic solids, which renders the family of SR [Formula: see text] schemes the first efficient 2Q recoupling option for general applications, such as 2Q-1Q correlation NMR and high-order multiple-quantum excitation, under truly low-power rf conditions.

  12. Slow-down of 13C spin diffusion in organic solids by fast MAS: a CODEX NMR Study.

    PubMed

    Reichert, D; Bonagamba, T J; Schmidt-Rohr, K

    2001-07-01

    One- and two-dimensional 13C exchange nuclear magnetic resonance experiments under magic-angle spinning (MAS) can provide detailed information on slow segmental reorientations and chemical exchange in organic solids, including polymers and proteins. However, observations of dynamics on the time scale of seconds or longer are hampered by the competing process of dipolar 13C spin exchange (spin diffusion). In this Communication, we show that fast MAS can significantly slow down the dipolar spin exchange effect for unprotonated carbon sites. The exchange is measured quantitatively using the centerband-only detection of exchange technique, which enables the detection of exchange at any spinning speed, even in the absence of changes of isotropic chemical shifts. For chemically equivalent unprotonated 13C sites, the dipolar spin exchange rate is found to decrease slightly less than proportionally with the sample-rotation frequency, between 8 and 28 kHz. In the same range, the dipolar spin exchange rate for a glassy polymer with an inhomogeneously broadened MAS line decreases by a factor of 10. For methylene groups, no or only a minor slow-down of the exchange rate is found.

  13. Formation and decomposition of N,N,N-trimethylanilinium cations on zeolite H-Y investigated by in situ stopped-flow MAS NMR spectroscopy.

    PubMed

    Wang, Wei; Seiler, Michael; Ivanova, Irina I; Sternberg, Ulrich; Weitkamp, Jens; Hunger, Michael

    2002-06-26

    Methylation of aniline by methanol on zeolite H-Y has been investigated by in situ (13)C MAS NMR spectroscopy under flow conditions. The in situ (13)C continuous-flow (CF) MAS NMR experiments were performed at reaction temperatures between 473 and 523 K, molar methanol-to-aniline ratios of 1:1 to 4:1, and modified residence times of (13)CH(3)OH between 20 and 100 (g x h)/mol. The methylation reaction was shown to start at 473 K. N,N,N-Trimethylanilinium cations causing a (13)C NMR signal at 58 ppm constitute the major product on the catalyst surface. Small amounts of protonated N-methylaniline ([PhNH(2)CH(3)](+)) and N,N-dimethylaniline ([PhNH(CH(3))(2)](+)) were also observed at ca. 39 and 48 ppm, respectively. After increase of the temperature to 523 K, the contents of N,N-dimethylanilinium cations and ring-alkylated reaction products strongly increased, accompanied by a decrease of the amount of N,N,N-trimethylanilinium cations. With application of the in situ stopped-flow (SF) MAS NMR technique, the decomposition of N,N,N-trimethylanilinium cations on zeolite H-Y to N,N-dimethylanilinium and N-methylanilinium cations was investigated to gain a deeper insight into the reaction mechanism. The results obtained allow the proposal of a mechanism consisting of three steps: (i) the conversion of methanol to surface methoxy groups and dimethyl ether (DME); (ii) the alkylation of aniline with methanol, methoxy groups, or DME leading to an equilibrium mixture of N,N,N-trimethylanilinium, N,N-dimethylanilinium, and N-methylanilinium cations attached to the zeolite surface; (iii) the deprotonation of N,N-dimethylanilinium and N-methylanilinium cations causing the formation of N,N-dimethylaniline (NNDMA) and N-methylaniline (NMA) in the gas phase, respectively. The chemical equilibrium between the anilinium cations carrying different numbers of methyl groups is suggested to play a key role for the products distribution in the gas phase.

  14. {sup 13}C chemical shift anisotropies for carbonate ions in cement minerals and the use of {sup 13}C, {sup 27}Al and {sup 29}Si MAS NMR in studies of Portland cement including limestone additions

    SciTech Connect

    Sevelsted, Tine F.; Herfort, Duncan

    2013-10-15

    {sup 13}C isotropic chemical shifts and chemical shift anisotropy parameters have been determined for a number of inorganic carbonates relevant in cement chemistry from slow-speed {sup 13}C MAS or {sup 13}C({sup 1}H) CP/MAS NMR spectra (9.4 T or 14.1 T) for {sup 13}C in natural abundance. The variation in the {sup 13}C chemical shift parameters is relatively small, raising some doubts that different carbonate species in Portland cement-based materials may not be sufficiently resolved in {sup 13}C MAS NMR spectra. However, it is shown that by combining {sup 13}C MAS and {sup 13}C({sup 1}H) CP/MAS NMR carbonate anions in anhydrous and hydrated phases can be distinguished, thereby providing valuable information about the reactivity of limestone in cement blends. This is illustrated for three cement pastes prepared from an ordinary Portland cement, including 0, 16, and 25 wt.% limestone, and following the hydration for up to one year. For these blends {sup 29}Si MAS NMR reveals that the limestone filler accelerates the hydration for alite and also results in a smaller fraction of tetrahedrally coordinated Al incorporated in the C-S-H phase. The latter result is more clearly observed in {sup 27}Al MAS NMR spectra of the cement–limestone blends and suggests that dissolved aluminate species in the cement–limestone blends readily react with carbonate ions from the limestone filler, forming calcium monocarboaluminate hydrate. -- Highlights: •{sup 13}C chemical shift anisotropies for inorganic carbonates from {sup 13}C MAS NMR. •Narrow {sup 13}C NMR chemical shift range (163–171 ppm) for inorganic carbonates. •Anhydrous and hydrated carbonate species by {sup 13}C MAS and {sup 13}C({sup 1}H) CP/MAS NMR. •Limestone accelerates the hydration for alite in Portland – limestone cements. •Limestone reduces the amount of aluminium incorporated in the C-S-H phase.

  15. Size- and site-dependent reconstruction in CdSe QDs evidenced by 77Se{1H} CP-MAS NMR spectroscopy.

    PubMed

    Lovingood, Derek D; Achey, Randall; Paravastu, Anant K; Strouse, Geoffrey F

    2010-03-17

    Evidence of size-dependent reconstruction in quantum dots leading to changes in bonding is observed through analysis of the (77)Se{(1)H} cross-polarization magic angle spinning and (77)Se spin-echo solid-state NMR for Cd(77)Se quantum dots. The CP-MAS and spin-echo data indicate discrete surface and core (77)Se sites exist with the QD, in which the surface is comprised of numerous reconstructed lattice planes. Due to the nearly 100% enrichment level for (77)Se, efficient spin coupling is observed between the surface (77)Se and sublayer (77)Se sites due to spin diffusion in the Cd(77)Se quantum dots. The observed chemical shift for the discrete (77)Se sites can be correlated to the effective mass approximation via the Ramsey expression, indicating a 1/r(2) size dependence for the change in chemical shift with size, while a plot of chemical shift versus the inverse band gap is linear. The correlation of NMR shift for the discrete sites allows a valence bond theory interpretation of the size-dependent changes in bonding character within the reconstructed QD. The NMR results provide a structural model for the QDs in which global reconstruction occurs below 4 nm in diameter, while an apparent self-limiting reconstruction process occurs above 4 nm.

  16. Investigation of the Use of Solid State Cp/mas NMR for Characterization of Thermoplastic Polyamides and Unique Thermally Curable Polyamides Containing the Cyclobutene Moiety.

    NASA Astrophysics Data System (ADS)

    Powell, Douglas Graham

    1990-08-01

    A series of model diamides was synthesized from mono- and disubstituted amines with the diacid chloride of cyclobutene-1,2-dicarboxylic acid. Relative rates of thermolysis (by DSC) were dependent on the number and type of substituents. Thermolysis products were Diels-Alder dimers and spontaneously formed polymers. Thermal imidization of cycloadducts was possible in some cases with concomitant oxidation to N, N^'-disubstituted aromatic bisimides. Polyamides were prepared from cyclobutene-1,2 -dicarboxylic acid using low temperature condensation reaction conditions. The unusual solubility characteristics of the diacid as well as the instability of the diacid chloride severely limited formation of high molecular weight polymers. Secondary monomers were synthesized in order to take advantage of the more predictable reactivity of the aromatic carboxyl group. Secondary monomers were polymerized with diamine comonomers using low temperature condensation methods. Solid state ^{13}C CP/MAS NMR confirmed the polymer structure. The thermalized product was found to be insoluble, although swellable, in polar aprotic solvents. Solid state ^{13 }C NMR spectra of the thermal products confirmed crosslinking by intermolecular Diels-Alder cycloaddition. Several important aliphatic polyamides were characterized using high resolution techniques with an emphasis on the ^{15}N nucleus. Chemical shifts from ^{15}N CP/MAS were found to correlate with the alpha and gamma crystal forms found in aliphatic polyamides. This chemical shift difference is rationalized as a conformationally dependent interaction of the amide nitrogen with its substituents. Evidence is presented from molecular orbital calculations which support this theory. Nylon 6 and nylon 11 were synthesized with 20% and 99% ^{15}N enrichment, respectively. ^{15}N CP/MAS of the enriched nylon 6 showed the amorphous region of the polymer for the first time. ^{15 }N relaxation times (T_1, T_1_rho) confirmed the assignment of the

  17. Constant-time 2D and 3D through-bond correlation NMR spectroscopy of solids under 60 kHz MAS

    SciTech Connect

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2016-01-21

    Establishing connectivity and proximity of nuclei is an important step in elucidating the structure and dynamics of molecules in solids using magic angle spinning (MAS) NMR spectroscopy. Although recent studies have successfully demonstrated the feasibility of proton-detected multidimensional solid-state NMR experiments under ultrafast-MAS frequencies and obtaining high-resolution spectral lines of protons, assignment of proton resonances is a major challenge. In this study, we first re-visit and demonstrate the feasibility of 2D constant-time uniform-sign cross-peak correlation (CTUC-COSY) NMR experiment on rigid solids under ultrafast-MAS conditions, where the sensitivity of the experiment is enhanced by the reduced spin-spin relaxation rate and the use of low radio-frequency power for heteronuclear decoupling during the evolution intervals of the pulse sequence. In addition, we experimentally demonstrate the performance of a proton-detected pulse sequence to obtain a 3D {sup 1}H/{sup 13}C/{sup 1}H chemical shift correlation spectrum by incorporating an additional cross-polarization period in the CTUC-COSY pulse sequence to enable proton chemical shift evolution and proton detection in the incrementable t{sub 1} and t{sub 3} periods, respectively. In addition to through-space and through-bond {sup 13}C/{sup 1}H and {sup 13}C/{sup 13}C chemical shift correlations, the 3D {sup 1}H/{sup 13}C/{sup 1}H experiment also provides a COSY-type {sup 1}H/{sup 1}H chemical shift correlation spectrum, where only the chemical shifts of those protons, which are bonded to two neighboring carbons, are correlated. By extracting 2D F1/F3 slices ({sup 1}H/{sup 1}H chemical shift correlation spectrum) at different {sup 13}C chemical shift frequencies from the 3D {sup 1}H/{sup 13}C/{sup 1}H spectrum, resonances of proton atoms located close to a specific carbon atom can be identified. Overall, the through-bond and through-space homonuclear/heteronuclear proximities determined from the

  18. Constant-time 2D and 3D through-bond correlation NMR spectroscopy of solids under 60 kHz MAS

    PubMed Central

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2016-01-01

    Establishing connectivity and proximity of nuclei is an important step in elucidating the structure and dynamics of molecules in solids using magic angle spinning (MAS) NMR spectroscopy. Although recent studies have successfully demonstrated the feasibility of proton-detected multidimensional solid-state NMR experiments under ultrafast-MAS frequencies and obtaining high-resolution spectral lines of protons, assignment of proton resonances is a major challenge. In this study, we first re-visit and demonstrate the feasibility of 2D constant-time uniform-sign cross-peak correlation (CTUC-COSY) NMR experiment on rigid solids under ultrafast-MAS conditions, where the sensitivity of the experiment is enhanced by the reduced spin-spin relaxation rate and the use of low radio-frequency power for heteronuclear decoupling during the evolution intervals of the pulse sequence. In addition, we experimentally demonstrate the performance of a proton-detected pulse sequence to obtain a 3D 1H/13C/1H chemical shift correlation spectrum by incorporating an additional cross-polarization period in the CTUC-COSY pulse sequence to enable proton chemical shift evolution and proton detection in the incrementable t1 and t3 periods, respectively. In addition to through-space and through-bond 13C/1H and 13C/13C chemical shift correlations, the 3D 1H/13C/1H experiment also provides a COSY-type 1H/1H chemical shift correlation spectrum, where only the chemical shifts of those protons, which are bonded to two neighboring carbons, are correlated. By extracting 2D F1/F3 slices (1H/1H chemical shift correlation spectrum) at different 13C chemical shift frequencies from the 3D 1H/13C/1H spectrum, resonances of proton atoms located close to a specific carbon atom can be identified. Overall, the through-bond and through-space homonuclear/heteronuclear proximities determined from the 3D 1H/13C/1H experiment would be useful to study the structure and dynamics of a variety of chemical and biological

  19. Efficient Resonance Assignment of Proteins in MAS NMR by Simultaneous Intra- and Inter-residue 3D Correlation Spectroscopy

    PubMed Central

    Daviso, Eugenio; Eddy, Matthew T.; Andreas, Loren B.; Griffin, Robert G.; Herzfeld, Judith

    2013-01-01

    Resonance assignment is the first step in NMR structure determination. For magic angle spinning NMR, this is typically achieved with a set of heteronuclear correlation experiments (NCaCX, NCOCX, CONCa) that utilize SPECIFIC-CP 15N-13C transfers. However, the SPECIFIC-CP transfer efficiency is often compromised by molecular dynamics and probe performance. Here we show that one-bond ZF-TEDOR 15N-13C transfers provide simultaneous NCO and NCa transfers with at least as much sensitivity as SPECIFIC-CP for some non-crystalline samples. Furthermore, a 3D TEDOR-CC experiment provides heteronuclear sidechains correlations and robustness with respect to proton decoupling and radiofrequency power instabilities. We demonstrate transfer efficiencies and connectivities by application of 3D ZF-TEDOR-DARR to a model microcrystalline protein, GB1, and a less ideal system, GvpA in intact gas vesicles. PMID:23334347

  20. Crystal structure of silica-ZSM-12 by the combined use of high-resolution solid-state MAS NMR spectroscopy and synchrotron x-ray powder diffraction

    SciTech Connect

    Fyfe, C.A.; Kokotailo, G.T. ); Gies, H.; Marler, B. ); Cox, D.E. )

    1990-05-03

    The crystal structure of the synthetic zeolite silica-ZSM-12, 56 SiO{sub 2}, has been solved by the combined use of high-resolution solid-state MAS NMR spectroscopy and high-resolution synchrotron X-ray powder diffraction ZSM-12 crystallizes in the monoclinic space group C2/c with a{sub 0} = 24.863 {angstrom}, b{sub 0} = 5.012 {angstrom}, c{sub 0} = 24.328 {angstrom}, and {beta} = 107.7{degree}. The zeolite host structure is built from corner-linked SiO{sub 4} tetrahedra to give a three-dimensional 4-connected net. The pores of the structure are one-dimensional channels that do not intersect, with 12-membered ring pore openings of approximately 5.6 {times} 7.7 {angstrom}. The structure of ZSM-12 is frequently twinned with (100) as the twin plane, which indicates a new zeolite structure type.

  1. In Situ High Temperature High Pressure MAS NMR Study on the Crystallization of AlPO 4 -5

    SciTech Connect

    Zhao, Zhenchao; Xu, Suochang; Hu, Mary Y.; Bao, Xinhe; Hu, Jian Zhi

    2016-01-28

    A damped oscillating crystallization process of AlPO4-5 at the presence of small amount of water is demonstrated by in situ high temperature high pressure multinuclear MAS NMR. Crystalline AlPO4-5 is formed from an intermediate semicrystalline phase via continuous rearrangement of the local structure of amorphous precursor gel. Activated water catalyzes the rearrangement via repeatedly hydrolysis and condensation reaction. Strong interactions between organic template and inorganic species facilitate the ordered rearrangement. During the crystallization process, excess water, phosphate, and aluminums are expelled from the precursor. The oscillating crystallization reflects mass transportation between the solid and liquid phase during the crystallization process. This crystallization process is also applicable to AlPO4-5 crystallized in the presence of a relatively large amount of water.

  2. 13C CP MAS NMR and GIAO-CHF/DFT calculations of flavonoids: Morin, kaempferol, tricin, genistein, formononetin and 3,7-dihydroxyflavone

    NASA Astrophysics Data System (ADS)

    Zielińska, Agnieszka; Paradowska, Katarzyna; Jakowski, Jacek; Wawer, Iwona

    2008-02-01

    13C CP MAS NMR spectra of the flavonoids: morin, kaempferol, 3,7-dihydroxyflavone, tricin and isoflavones: genistein and formononetin were recorded to characterize solid-state conformations. Intramolecular hydrogen bonds forming five-, six- and seven-membered rings are present in the two morin molecules in the crystals - their 13C resonances have been assigned with the aid of the calculated shielding constants. Linear relationships between the calculated shielding constants σDFT (ppm) and chemical shifts ( δCPMAS, ppm) were obtained for all studied compounds. Higher correlation coefficients suggest that the conformation with "clockwise" orientation of both OH groups is more probable in the solid 3,7-dihydroxyflavone, whereas in the solid formononetin the OH and OCH 3 substituents are directed "anticlockwise". The barrier to the rotation of phenyl ring B decreases in the order: morin (2'-OH, 3-OH) > kaempferol (3-OH) > tricin.

  3. A study of structure and dynamics of poly(aspartic acid) sodium/poly(vinyl alcohol) blends by 13C CP/MAS NMR

    NASA Astrophysics Data System (ADS)

    Wang, P.; Ando, I.

    1999-09-01

    Solid state 13C CP/MAS NMR measurements have been carried out on poly(aspartic acid) sodium (PAANa)/poly(vinyl alcohol) (PVA) blends over a wide range of temperatures. From these experimental results, it is found that the main-chain conformations of PAANa in PAANa/PVA blends take the α-helix form over a wide range of blend ratios, and, in contrast, the conformation and dynamics of the side chains of PAANa are strongly influenced by the formation of an intermolecular hydrogen bond between the carboxyl group of the side chains and the hydroxyl group of PVA. The behavior of the proton spin-lattice relaxation times in the rotating frame ( T1 ρ(H)) and the laboratory frame ( T1(H)) indicates that when the blend ratio of PAANa and PVA is 1:1, they are miscible.

  4. Modification of structure and digestibility of chestnut starch upon cooking: a solid state (13)C CP MAS NMR and enzymatic degradation study.

    PubMed

    Pizzoferrato, L; Rotilio, G; Paci, M

    1999-10-01

    The modification of starch, which is the major component of the polysaccharide fraction of chestnuts (Castanea sativa), has been studied from the point of view of structure and digestibility to understand the modifications induced by cooking and, specifically, by the Maillard reaction. The study was carried out by enzymatic degradation kinetics, monitoring the glucose released upon time, and by solid state (13)C CP MAS NMR, which has the potential of monitoring the solid state phase changes occurring upon chemical modification due to the cooking process. Results obtained reveal that large changes are induced in the macromolecular structure of starchy materials and that these changes are correlated with changes of digestibility in terms of enzymatic degradation resistance. In the system studied, the extension of the Maillard reaction is not such as to exert a significant influence on structure and/or digestibility of chestnut starch.

  5. (119)Sn MAS NMR and first-principles calculations for the investigation of disorder in stannate pyrochlores.

    PubMed

    Mitchell, Martin R; Reader, Simon W; Johnston, Karen E; Pickard, Chris J; Whittle, Karl R; Ashbrook, Sharon E

    2011-01-14

    The local structure and cation disorder in Y(2)Ti(2-x)Sn(x)O(7) pyrochlores, materials proposed for the encapsulation of lanthanide- and actinide-bearing radioactive waste, is studied using (119)Sn (I = 1/2) NMR spectroscopy. NMR provides an excellent probe of disorder, as it is sensitive to the atomic scale environment without the need for any long-range periodicity. However, the complex and overlapping spectral resonances that often result can be difficult to interpret. Here, we demonstrate how (119)Sn DFT calculations can be used to aid the spectral interpretation and assignment, confirming that Sn occupies only the six-coordinate pyrochlore B site, and that the Sn chemical shift is sensitive to the number of Sn/Ti on the neighbouring B sites. Although distinct resonances are resolved experimentally when the Ti content is low, there is significant spectral overlap for Ti-rich compositions. We establish that this is a result of two competing contributions to the Sn chemical shift; an upfield shift resulting from the incorporation of the more polarizing Ti(4+) cation onto the neighbouring B sites, and a concomitant downfield shift arising from the decrease in unit cell size. Despite the considerably easier spectral acquisition, the lower resolution in the (119)Sn spectra hinders the extraction of the detailed structural information previously obtained using (89)Y NMR. However, the spectra we obtain are consistent with a random distribution of Sn/Ti on the pyrochlore B sites. Finally, we consider whether an equilibrium structure has been achieved by investigating materials that have been annealed for different durations.

  6. Synthesis, Infra-red, CP/MAS-NMR characterization, structural study and electrical properties of the bis(4-amino-2-chloropyridinium) tetrachlorozincate (II) monohydrate

    NASA Astrophysics Data System (ADS)

    Karâa, Najla; Hamdi, Besma; Ben Salah, Abdelhamid; Zouari, Ridha

    2013-10-01

    Single crystals of the new ionic salt bis(4-amino-2-chloropyridinium) tetrachlorozincate (II) monohydrate, (C5H6N2Cl)2 ZnCl4ṡH2O, were grown by slow evaporation from aqueous solution at room temperature. The compound was characterized by IR, thermal analysis (TGA-DSC), single crystal X-ray diffraction, CP/MAS-NMR and impedance spectroscopy. The structure (4-amino-2-chloropyridinium)2 ZnCl4·H2O, [(CAP)2ZnCl4·H2O], consists of isolated H2O, isolated [ZnCl4]2- tetrahedral anions and 4-amino-2-chloropyridinium [C5H6N2Cl] + cations, CAP, which are connected together via N-H⋯Cl, N-H⋯O ((N: pyridinium) and (N: amine)), O-H⋯Cl and C-H⋯Cl hydrogen bonds. Cation-cation, offset-face-to-face interactions (π-π stacking) between identical antiparallel CAP (aromatic-aromatic), in which they may be effective in the stabilization of the crystal structure. Solid state CP/MAS-NMR spectra showed five isotropic resonances, 13C, confirming the solid state structure determined by X-ray diffraction. Impedance spectroscopy study, reported for a single crystal, revealed that the conduction in the material was due to a hopping process. This work aims to reveal the thermal properties of a new zinc (II) based organic-inorganic hybrid and the conductivity properties that these compounds exhibit.

  7. 29Si{1H} CP-MAS NMR comparison and ATR-FTIR spectroscopic analysis of the diatoms Chaetoceros muelleri and Thalassiosira pseudonana grown at different salinities.

    PubMed

    La Vars, Sian M; Johnston, Martin R; Hayles, John; Gascooke, Jason R; Brown, Melissa H; Leterme, Sophie C; Ellis, Amanda V

    2013-04-01

    Diatoms are key indicators of marine environmental health. To further understand how diatoms respond to varying degrees of salinity, either due to climate change or brine waste discharge into marine environments, two different diatom species were studied. Thalassiosira pseudonana and Chaetoceros muelleri were cultured at three different salinities namely, 26 practical salinity units (PSU or parts per thousand), 36 PSU (standard salinity for culturing of seawater species) and 46 PSU. Changes in silica and organic content within the cultured diatoms were analysed using solid-state (29)Si{(1)H} cross-polarization-magic angle spinning (CP-MAS) nuclear magnetic resonance (NMR) and attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopies coupled with analysis of variance. (29)Si CP-MAS NMR showed that qualitatively the Q4:Q3 area ratios of C. muelleri, grown away from standard salinities, increased in response to the formation of more condensed (2 ≡SiOH → ≡Si-O-Si≡ + H2O) and/or an increase in closely associated organic matter to the Q4 component of the diatoms. This was not observed for T. pseudonana. However, both species showed the appearance of a new peak centered at 1575-1580 cm(-1) in the ATR-FTIR spectra, designated as the C═N band of nitrogenous purine-type compounds. Further, the C. muelleri species was shown to produce more extracellular polymeric substances at non-standard salinities. On this basis, results suggest that there is a strong relationship between diatom composition and salinity and that C. muelleri is more sensitive to its environment than T. pseudonana.

  8. Structural investigations of PuIII phosphate by X-ray diffraction, MAS-NMR and XANES spectroscopy

    NASA Astrophysics Data System (ADS)

    Popa, Karin; Raison, Philippe E.; Martel, Laura; Martin, Philippe M.; Prieur, Damien; Solari, Pier L.; Bouëxière, Daniel; Konings, Rudy J. M.; Somers, Joseph

    2015-10-01

    PuPO4 was prepared by a solid state reaction method and its crystal structure at room temperature was solved by powder X-ray diffraction combined with Rietveld refinement. High resolution XANES measurements confirm the +III valence state of plutonium, in agreement with valence bond derivation. The presence of the americium (as β- decay product of plutonium) in the +III oxidation state was determined based on XANES spectroscopy. High resolution solid state 31P NMR agrees with the XANES results and the presence of a solid-solution.

  9. Influence of sodium ion dynamics on the 23Na quadrupolar interaction in sodalite: a high-temperature 23Na MAS NMR study.

    PubMed

    Fechtelkord, M

    2000-01-01

    High-temperature 33Na MAS NMR experiments up to 873 K for a number of different sodalites (Na8[AlSiO4]6(NO3)2, Na8[AlSiO4]6(NO2)2, Na8[AlSiO4]6I2, Na7.9[AlSiO4]6(SCN)7.9 x 0.5H2O, Na8[AlGeO4]6(NO3)2, and Na7[AlSiO4]6(H3O2) x 4H2O) were carried out. The spectra of the first five sodalites consist of a quadrupolar MAS pattern with different quadrupolar coupling constants. The quadrupolar interaction for the thiocyanate sodalite, the nitrate aluminosilicate, and germanate sodalite decreases strongly passing a coalescence state on heating, while the quadrupolar interaction of the iodide and nitrite sample shows nearly no change. The basic hydrosodalite shows an asymmetric lineshape at room temperature and, between 350 and 370 K, a second line due to the evaporation of cage-water emerges. The linewidth increases with rising temperature. The temperature dependence of the quadrupolar interaction seems to be a function of the sodalite beta-cage expansion. Two conceivable jump mechanisms are proposed for a tetrahedral two-site jump between occupied and unoccupied tetrahedral sites.

  10. Solubilization and localization of weakly polar lipids in unsonicated egg phosphatidylcholine: A sup 13 C MAS NMR study

    SciTech Connect

    Hamilton, J.A. ); Fujito, D.T.; Hammer, C.F. )

    1991-03-19

    The weakly polar lipids cholesteryl ester, triacylglycerol, and diacylglycerol incorporate to a limited extent into the lamellar structure of small unilamellar vesicles. The localization of the carbonyl group(s) at the aqueous interface was detected by ({sup 13}C)carbonyl chemical shift changes relative to the neat unhydrated lipid. This study uses {sup 13}C NMR to investigate the interactions of thes lipids with unsonicated (multilamellar) phosphatidylcholine, a model system for cellular membranes and surfaces of emulsion particles with low curvature. Magic angle spinning reduced the broad lines of the unsonicated dispersions to narrow lines comparable to those from sonicated dispersions. ({sup 13}C)Carbonyl chemical shifts revealed incorporation of the three lipids into the lamellar structure of the unsonicated phospholipids and a partial hydration of the carbonyl groups similar to that observed in small vesicles. Other properties of interfacial weakly polar lipids in multilayers were similar to those in small unilamellar bilayers. There is thus a general tendency of weakly polar lipids to incorparate at least to a small extent into the lamellar structure of phospholipids and take on interfacial properties that are distinct from their bulk-phase properties. This pool of surface-located lipid is likely to be directly involved in enzymatyic transformations and protein-mediated transport. The {sup 13}C magic angle spinning NMR method may be generally useful for determining the orientation of molecules in model membranes.

  11. Investigation of the Structure and Active Sites of TiO2 Nanorod Supported VOx Catalysts by High-Field and Fast-Spinning 51V MAS NMR

    SciTech Connect

    Hu, Jian Z.; Xu, Suochang; Li, Weizhen; Hu, Mary Y.; Deng, Xuchu; Dixon, David A.; Vasiliu, Monica; Craciun, Raluca; Wang, Yong; Bao, Xinhe; Peden, Charles HF

    2015-07-02

    Supported VOx/TiO2-Rod catalysts were studied by 51V MAS NMR at high field using a sample spinning rate of 55 kHz. The superior spectral resolution allows for the observation of at least five vanadate species. The assignment of these vanadate species was carried out by quantum mechanical calculations of 51V NMR chemical shifts of model V-surface structures. Methanol oxidative dehydrogenation (ODH) was used to establish the correlation between the reaction rate and the various surface V-sites. It is found that monomeric V-species dominated the catalyst at low vanadium loadings with two peaks observed at about -502 and -529 ppm. V-dimers with two bridged oxygen appeare at about -555 ppm. Vanadate dimers and polyvanadates connected by one bridged oxygen atom between two adjacent V atoms resonate at about -630 ppm. A positive correlation is found between the V-dimers related to the -555 ppm peak and the ODH rate while a better correlation is obtained by including monomeric contributions. This result indicates that surface V-dimers related to the -555 ppm peak are the major active sites for ODH reaction despite mono-V species are more catalytic active but their relative ratios are decreased dramatically at high V-loadings. Furthermore, a portion of the V-species is found invisible. In particular, the level of such invisibility increases with decreased level of V-loading, suggesting the existence of paramagnetic V-species at the surface.

  12. Structure of SiO[sub 2] on Al[sub 2]O[sub 3] monolayer catalysts: Investigation by infrared spectroscopy and [sup 29]Si MAS NMR

    SciTech Connect

    Sheng, T.C. ); Lang, S.; Morrow, B.A. ); Gay, I.D. )

    1994-07-01

    Infrared spectroscopy and [sup 29]Si MAS NMR are used to probe the structure of SiO[sub 2] on Al[sub 2]O[sub 3] catalysts prepared by chemical vapor deposition of Si(OCH[sub 3])[sub 4][center dot]SiO[sub 2] loadings from about 0.2-2.5 statistical monolayers are studied. Infrared shows a gradual disappearance of AlOH vibrations as the SiO[sub 2] loading is increased. A population of inaccessible AlOH is also observed. The Si-O-X asymmetric stretching frequency shows a continuous variation with SiO[sub 2] content, consistent with X varying from Al at low levels to Si at high levels of silica. [sup 29]Si NMR shows composite peaks at all SiO[sub 2] levels. At the lowest level most intensity is concentrated in the -80 to -85 ppm range, corresponding to Si with attached -OAl groups. At the highest silica levels, the spectrum can be deconvoluted into peaks at -108, -100, and -92 ppm. These correspond to Si(OSi)[sub 4], Si(OSi)[sub 3]OH, and mixtures of Si(OSi)[sub 2](OH)[sub 2] with -OAl-containing species. A model is proposed for build up of the silica layer on these catalysts. Random deposition of silica on any available surface is shown to give a semiquantitative account of the experimental results. 31 refs., 6 fig., 2 tabs.

  13. Proton-detected MAS NMR experiments based on dipolar transfers for backbone assignment of highly deuterated proteins

    NASA Astrophysics Data System (ADS)

    Chevelkov, Veniamin; Habenstein, Birgit; Loquet, Antoine; Giller, Karin; Becker, Stefan; Lange, Adam

    2014-05-01

    Proton-detected solid-state NMR was applied to a highly deuterated insoluble, non-crystalline biological assembly, the Salmonella typhimurium type iii secretion system (T3SS) needle. Spectra of very high resolution and sensitivity were obtained at a low protonation level of 10-20% at exchangeable amide positions. We developed efficient experimental protocols for resonance assignment tailored for this system and the employed experimental conditions. Using exclusively dipolar-based interspin magnetization transfers, we recorded two sets of 3D spectra allowing for an almost complete backbone resonance assignment of the needle subunit PrgI. The additional information provided by the well-resolved proton dimension revealed the presence of two sets of resonances in the N-terminal helix of PrgI, while in previous studies employing 13C detection only a single set of resonances was observed.

  14. Al speciation in tropical podzols of the upper Amazon Basin: A solid-state 27Al MAS and MQMAS NMR study

    NASA Astrophysics Data System (ADS)

    Bardy, Marion; Bonhomme, Christian; Fritsch, Emmanuel; Maquet, Jocelyne; Hajjar, Redouane; Allard, Thierry; Derenne, Sylvie; Calas, Georges

    2007-07-01

    In the upper Amazon Basin, aluminum previously accumulated in lateritic formations is massively remobilised in soils by podzolization and exported in waters. We have investigated the speciation of aluminum in the clay-size fractions of eight horizons of waterlogged podzols lying in a depression of a plateau. The horizons illustrate the main steps involved in the podzolization of laterites. They belong to eluviated topsoil A horizons and illuviated subsoil Bhs, Bh and 2BCs horizons of weakly and better-expressed podzols located at the margin and centre of the depression. For the first time, aluminum speciation is quantitatively assessed in soils by spectroscopic methods, namely FTIR, 27Al magic angle spinning (MAS) and multiple-quantum magic angle spinning (MQMAS), nuclear magnetic resonance (NMR). The results thus obtained are compared to chemical extraction data. Solid-state 27Al MAS NMR spectra enable to distinguish Al bound to organic compounds from that incorporated in secondary mineral phases detected by FTIR. MQMAS experiments additionally show that both chemical shifts and quadrupolar constants are distributed for Al nuclei linked with organic compounds. Similar amounts of chelated Al are obtained from NMR spectra and chemical extractions. The study enables to highlight three major steps in the fate of aluminum. (i) Aluminum is first released by mineral weathering, feeds complexing sites of organic matter and accumulates in subsurface Bhs horizons of weakly expressed podzols (acidocomplexolysis). (ii) Complexes of aluminum with organic matter (Al-OM) then migrate downwards in sandy horizons of better-expressed podzols and accumulate at depth in less permeable 2BCs horizons. (iii) The minor amounts of aluminum present in the 2BCs horizon of the downslope podzol show that aluminum is eventually exported towards the river network, either complexed with organic matter or as Al 3+ ions after desorption from organic compounds, due to decreasing pH or

  15. Atomic structure and dehydration mechanism of amorphous silica: Insights from 29Si and 1H solid-state MAS NMR study of SiO2 nanoparticles

    NASA Astrophysics Data System (ADS)

    Kim, Hyun Na; Lee, Sung Keun

    2013-11-01

    Detailed knowledge of the atomic structure of hydrous species on surface of amorphous silica and the effect of temperature and particle size on their atomic configurations are essential to understand the nature of fluids-amorphous silicates interactions and the dehydration processes in the amorphous oxides. Here, we report the 29Si, 1H MAS, and 1H-29Si heteronuclear correlation (HetCor) NMR spectra of 7 nm and 14 nm amorphous silica nanoparticles—a model system for natural amorphous silica—where previously unknown details of changes in their atomic structures with varying dehydration temperature and particle size are revealed. Diverse hydroxyl groups with varying atomic configurations and molecular water apparently show distinct dehydration trends. The dehydration (i.e., removal of water) of amorphous silica nanoparticles mostly results in the increase of isolated silanol by removing water molecules from hydrogen-bonded silanols associated water molecules. With further increase in dehydration temperature, the intensity of isolated silanol peak decreases above ˜873 K, suggesting that the condensation of isolated silanol may occur mainly above ˜873 K. The entire dehydration (and dehydroxylation) process completes at ˜1473 K. Both the water (i.e., physisorbed water and hydrogen-bonded water) and hydrogen-bonded silanol species show a dramatic change in the slope of intensity variation at ˜873 K, indicating that most of silanols is hydrogen-bonded to water rather than to other silanols. The fraction of hydrogen-bonded proton species is also much smaller in 14 nm amorphous silica nanoparticles than in 7 nm amorphous silica nanoparticles mainly due to the presences of larger fractions of water and hydrogen-bonded silanol species. 29Si NMR results show that with increasing dehydration temperature, the fraction of Q4 species apparently increases at the expense of Q2 and Q3 species. The fractions of Q2 and Q3 structures in 7 nm amorphous silica nanoparticles are

  16. 87Rb spin-lattice relaxation times in ferroelectric-paraelectric-incommensurate phases of Rb2CoBr4 using static NMR and MAS NMR

    NASA Astrophysics Data System (ADS)

    Lim, Ae Ran

    2017-04-01

    To better elucidate the structural properties of Rb2CoBr4 in paraelectric, incommensurate, and ferroelectric phases, we studied the 87Rb nuclear magnetic resonance (NMR) spectra and spin-lattice relaxation times in laboratory frame T1 and in rotating frame T1ρ. The resonance frequency and the chemical shift do not change abruptly near the phase transition temperature of Ti = 333 K and TC = 192 K, whereas T1 and T1ρ display discontinuous changes near Ti and TC. The abrupt changes in the relaxation times near these temperatures seem to be a result of the structural phase transitions. The results are distinctly different from those reported for Rb2CoCl4.

  17. Drug release from cast films of ethylene vinyl acetate (EVA) copolymer: Stability of drugs by 1H NMR and solid state 13C CP/MAS NMR.

    PubMed

    Kalachandra, S; Lin, D M; Stejskal, E O; Prakki, A; Offenbacher, S

    2005-07-01

    The study utilizes an oral biocompatible material based on ethylene vinyl acetate copolymer (EVA) designed to release drugs in vitro at therapeutic levels over several days. We examined the drug stability during film casting process using proton and solid state NMR techniques. The drug-loaded EVA films were prepared from the dry sheet obtained by solvent (dichloromethane) evaporation of polymer casting solutions. Drugs tested include chlorhexidine diacetate (CDA), doxycycline hydrochloride (DOH), tetracycline hydrochloride (TTH) and nystatin (NST). Drug release from the films was examined for at least 14 days in 10 ml ddH2O (NST in water/ethanol (4:1)) which was replaced daily. Changes in optical density were followed spectraphotometrically. Effect of temperature on rate measurements was studied and the energies of activation (E*) were calculated using Arrhenius plots. Effect of EVA copolymer composition on CDA release rate was also investigated. The enhanced rates with temperature increase may be attributed to the formation of channels with increased geometry in the polymer. The highest E* observed for CDA compared to DOH and TTH may be related to their average molecular weights. Spectral analyses for CDA and NST revealed that the chemical and physical structures of the drugs remained unaffected during the film casting process.

  18. 31P MAS-NMR study of flux-grown rare-earth element orthophosphate (monazite/xenotime) solid solutions: Evidence of random cation distribution from paramagnetically shifted NMR resonances

    SciTech Connect

    Palke, A. C.; Stebbins, J. F.; Boatner, Lynn A

    2013-01-01

    We present 31P magic angle spinning nuclear magnetic resonance (MAS-NMR) spectra of flux-grown solid solutions of La1-xCexPO4 ( x between 0.027 and 0.32) having the monoclinic monazite structure, and of Y1-xMxPO4 (M = Vn+, Ce3+, Nd3+, x between 0.001 and 0.014) having the tetragonal zircon structure. Paramagnetically shifted NMR resonances are observed in all samples due to the presence of paramagnetic Vn+, Ce3+, and Nd3+ in the diamagnetic LaPO4 or YPO4. As a first-order observation, the number and relative intensity of these peaks is related to the symmetry and structure of the diamagnetic host phase. The presence of paramagnetic shifts allows for increased resolution between NMR resonances for distinct atomic species which leads to the observation of low intensity peaks related to PO4 species having more than one paramagnetic neighbor two or four atomic bonds away. Through careful analysis of peak areas and comparison with predictions for simple models, it was determined that solid solutions in the systems examined here are characterized by complete disorder (random distribution) of diamagnetic La3+ or Y3+ with the paramagnetic substitutional species Ce3+ and Nd3+. The increased resolution given by the paramagnetic interactions also leads to the observation of splitting of specific resonances in the 31P NMR spectra that may be caused by local, small-scale distortions from the substitution of ions having dissimilar ionic radii.

  19. In situ (1)H and (13)C MAS NMR kinetic study of the mechanism of H/D exchange for propane on zeolite H-ZSM-5.

    PubMed

    Arzumanov, Sergei S; Reshetnikov, Sergei I; Stepanov, Alexander G; Parmon, Valentin N; Freude, Dieter

    2005-10-27

    The kinetics of hydrogen (H/D) exchange between Brønsted acid sites of zeolite H-ZSM-5 and variously deuterated propanes (propane-d(8), propane-1,1,1,3,3,3-d(6), propane-2,2-d(2)) have been monitored in situ by (1)H MAS NMR spectroscopy within the temperature range of 503-556 K. The contribution of intramolecular hydrogen transfer to the H/D exchange in the adsorbed propane was estimated by monitoring the kinetics of (13)C-labeled carbon scrambling in propane-2-(13)C in situ with (13)C MAS NMR at 543-573 K. Possible mechanisms of the exchange have been verified on the basis of the analysis of the variation of protium concentration in both the methyl and the methylene groups of propane in dependence of the reaction time. The main route of the exchange consists of a direct exchange of the acidic OH groups of the zeolite with either the methyl groups or the methylene group presumably with a pentacoordinated carbonium ion intermediate. The assumption that the intramolecular H scrambling between the methyl groups and the methylene group of propane via carbenium-ion-type intermediates is the fastest process among the other possible routes does not account for the experimental kinetics of H/D exchange for propanes with different initial contents and locations of deuterium in a propane molecule. The rate constant (k(3)) for intramolecular H/D exchange between the methyl and the methylene groups is 4-5 times lower compared to those of the direct exchange of both the methyl (k(1)) and the methylene (k(2)) groups with Brønsted acid sites of the zeolite, the k(1) being ca. 1.5 times higher than k(2). At lower temperature (473 K), the exchange is slower, and the expected difference between k(1) and k(2) is more essential, k(1) = 3k(2). This accounts for earlier observed regioselectivity of the exchange for propane on H-ZSM-5 at 473 K. Faster direct exchange with the methyl groups compared to that with the methylene groups was attributed to a possible, more spatial

  20. Effect of organic matter application on CP-MAS-13C-NMR spectra of humic acids from a brown soil

    NASA Astrophysics Data System (ADS)

    Dou, S.

    2009-04-01

    The humified SOM or humic substances (HS) composed of humic acid (HA), fulvic acid (FA) and humin (HM) represent the most microbially recalcitrant and stable reservoir of organic carbon in soil (Piccolo et al., 2004). OM applications can influence the amount and structural characteristics of HS(Dou et al., 2008). During the past few decades, there has been much research on HS, but their chemical structure is still not fully understood (Dong, 2006).CP-MAS-13C-NMR spectroscopy was considered as an effective method to study structures of HS without dissolving problem compared with liquid 13C-NMR (Conte et al., 1997; Dou et al., 2008). It can directly measure the carbon framework and reflect the nature of HS transformation after OM application (Spaccini et al., 2000). For that reason, this method was applied in this study. The objective of this paper was to clarify the effect of long term OM application on the changes of structural characteristics in HAs, which provided new information for improving soil fertility by OM application. The experiment was carried out on a brown soil (Paleudalf in USDA Soil Taxonomy) at Shenyang Agricultural University, Liaoning province, China (N41°48'-E123°25'). The experiment included 3 treatments: zero-treatment (CKbr), and two pig manure (PM) treatments (O1 and O2) at the rates of 0.9 t ha-1 and 1.8 t ha-1 of organic carbon, respectively. The samples of the HA fraction were extracted, separated and purified according to the method described by Dou et al. (1991). Elemental composition, Differential thermal analysis (DTA), -lgK value, FT-IR and CP-MAS- 13C-NMR of HAs were performed. Effects on the contents of orgaic carbon and its composition. The contents of TOC were from 8.77 g kg-1 to 12.25 g kg-1. The relative contents in TOC for WSS, HA, and FA were 6.87%, 14.2% and 19.8%. Comparing the CKbr, the contents of WSS, HA and FA for O1 and O2 increased, but relative contents of WSS and FA decreased. The content of the HA increased after

  1. Analysis of local molecular motions of aromatic sidechains in proteins by 2D and 3D fast MAS NMR spectroscopy and quantum mechanical calculations.

    PubMed

    Paluch, Piotr; Pawlak, Tomasz; Jeziorna, Agata; Trébosc, Julien; Hou, Guangjin; Vega, Alexander J; Amoureux, Jean-Paul; Dracinsky, Martin; Polenova, Tatyana; Potrzebowski, Marek J

    2015-11-21

    We report a new multidimensional magic angle spinning NMR methodology, which provides an accurate and detailed probe of molecular motions occurring on timescales of nano- to microseconds, in sidechains of proteins. The approach is based on a 3D CPVC-RFDR correlation experiment recorded under fast MAS conditions (ν(R) = 62 kHz), where (13)C-(1)H CPVC dipolar lineshapes are recorded in a chemical shift resolved manner. The power of the technique is demonstrated in model tripeptide Tyr-(d)Ala-Phe and two nanocrystalline proteins, GB1 and LC8. We demonstrate that, through numerical simulations of dipolar lineshapes of aromatic sidechains, their detailed dynamic profile, i.e., the motional modes, is obtained. In GB1 and LC8 the results unequivocally indicate that a number of aromatic residues are dynamic, and using quantum mechanical calculations, we correlate the molecular motions of aromatic groups to their local environment in the crystal lattice. The approach presented here is general and can be readily extended to other biological systems.

  2. A (1)H HR-MAS NMR-Based Metabolomic Study for Metabolic Characterization of Rice Grain from Various Oryza sativa L. Cultivars.

    PubMed

    Song, Eun-Hye; Kim, Hyun-Ju; Jeong, Jaesik; Chung, Hyun-Jung; Kim, Han-Yong; Bang, Eunjung; Hong, Young-Shick

    2016-04-20

    Rice grain metabolites are important for better understanding of the plant physiology of various rice cultivars and thus for developing rice cultivars aimed at providing diverse processed products. However, the variation of global metabolites in rice grains has rarely been explored. Here, we report the identification of intra- or intercellular metabolites in rice (Oryza sativa L.) grain powder using a (1)H high-resolution magic angle spinning (HR-MAS) NMR-based metabolomic approach. Compared with nonwaxy rice cultivars, marked accumulation of lipid metabolites such as fatty acids, phospholipids, and glycerophosphocholine in the grains of waxy rice cultivars demonstrated the distinct metabolic regulation and adaptation of each cultivar for effective growth during future germination, which may be reflected by high levels of glutamate, aspartate, asparagine, alanine, and sucrose. Therefore, this study provides important insights into the metabolic variations of diverse rice cultivars and their associations with environmental conditions and genetic backgrounds, with the aim of facilitating efficient development and the improvement of rice grain quality through inbreeding with genetic or chemical modification and mutation.

  3. Effects of solvent concentration and composition on protein dynamics: 13C MAS NMR studies of elastin in glycerol-water mixtures.

    PubMed

    Demuth, Dominik; Haase, Nils; Malzacher, Daniel; Vogel, Michael

    2015-08-01

    We use (13)C CP MAS NMR to investigate the dependence of elastin dynamics on the concentration and composition of the solvent at various temperatures. For elastin in pure glycerol, line-shape analysis shows that larger-scale fluctuations of the protein backbone require a minimum glycerol concentration of ~0.6 g/g at ambient temperature, while smaller-scale fluctuations are activated at lower solvation levels of ~0.2 g/g. Immersing elastin in various glycerol-water mixtures, we observe at room temperature that the protein mobility is higher for lower glycerol fractions in the solvent and, thus, lower solvent viscosity. When decreasing the temperature, the elastin spectra approach the line shape for the rigid protein at 245 K for all studied samples, indicating that the protein ceases to be mobile on the experimental time scale of ~10(-5) s. Our findings yield evidence for a strong coupling between elastin fluctuations and solvent dynamics and, hence, such interaction is not restricted to the case of protein-water mixtures. Spectral resolution of different carbon species reveals that the protein-solvent couplings can, however, be different for side chain and backbone units. We discuss these results against the background of the slaving model for protein dynamics.

  4. Solid-state MAS NMR, TEM, and TGA studies of structural hydroxyl groups and water in nanocrystalline apatites prepared by dry milling.

    PubMed

    Pajchel, Lukasz; Kolodziejski, Waclaw

    2013-01-01

    A series of nanocrystalline calcium hydroxyapatites was prepared by dry milling and characterized using proton and (31)P MAS NMR, TEM, and TGA methods. The samples contained stubby rod-shaped crystals, which length and width varied in the 130-30 and 95-20 nm ranges, respectively. It was confirmed that concentration of structural hydroxyl groups in nanocrystalline apatites decreases with the decreasing crystal size. In the series of the studied apatites, the decrease was from 86 to ca. 50 % in reference to stoichiometric apatite. Water was found in the surface hydrated layer and in the c-axis channels, in which compartments existed as adsorbed and structural, respectively. Molecules of the adsorbed water were capable of moving from the crystal surface into the lattice c-axis channels of apatite. This process introduced considerable structural disorder within and around those channels and reduced the content of the structural hydroxyl groups, particularly in the region underneath the apatite crystal surface.

  5. A sequential assignment procedure for proteins that have intermediate line widths in MAS NMR spectra: amyloid fibrils of human CA150.WW2.

    PubMed

    Becker, Johanna; Ferguson, Neil; Flinders, Jeremy; van Rossum, Barth-Jan; Fersht, Alan R; Oschkinat, Hartmut

    2008-08-11

    The second WW domain (WW2) of CA150, a human transcriptional activator, forms amyloid fibrils in vitro under physiological conditions. Based on experimental constraints from MAS NMR spectroscopy experiments, alanine scanning and electron microscopy, a structural model of CA150.WW2 amyloid fibrils was calculated earlier. Here, the assignment strategy is presented and suggested as a general approach for proteins that show intermediate line width. The (13)C,(13)C correlation experiments were recorded on fully or partially (13)C-labelled fibrils. The earlier (13)C assignment (26 residues) was extended to 34 of the 40 residues by direct (13)C-excitation experiments by using a deuterated sample that showed strongly improved line width. A 3D HNC-TEDOR (transferred-echo double-resonance) experiment with deuterated CA150.WW2 fibrils yielded 14 amide nitrogen and proton resonance assignments. The obtained chemical shifts were compared with the chemical shifts determined with the natively folded WW domain. TALOS (Torsion angle likelihood obtained from shift and sequence similarity) predictions confirmed that, under physiological conditions, the fibrillar form of CA150.WW2 adopts a significantly different beta structure than the native WW-domain fold.

  6. I: Low Frequency NMR and NQR Using a dc SQUID. II: Variable-temperature 13C CP/MAS of Organometallics

    SciTech Connect

    Ziegeweid, Marcia A.

    1995-11-01

    NMR and NQR at low frequencies are difficult prospects due to small nuclear spin polarization. Furthermore, the sensitivity of the inductive pickup circuitry of standard spectrometers is reduced as the frequency is lowered. I have used a cw-SQUID (Superconducting Quantum Interference Device) spectrometer, which has no such frequency dependence, to study the local atomic environment of 14N via the quadrupolar interaction. Because 14N has spin I = 1 and a 0-6 MHz frequency range, it is not possible to obtain well-resolved spectra in high magnetic fields. I have used a technique to observe 14N NQR resonances via their effect on neighboring protons mediated by the heteronuclear dipolar interaction to study peptides and narcotics. The sensitivity of the SQUID is not enough to measure low-frequency surface (or other low spin density) systems. The application of spin-polarized xenon has been previously used to enhance polarization in conventional NMR experiments. Because xenon only polarizes spins with which it is in contact, it is surface selective. While differences in chemical shifts between surface and bulk spins are not large, it is expected that the differences in quadrupole coupling constant should be very large due to the drastic change of the electric field gradient surrounding spins at the surface. With this in mind, I have taken preliminary steps to measure SQUID detected polarization transfer from Xe to another spin species at 4.2 K and in small magnetic fields (<50 G). In this regime, the spin-lattice relaxation of xenon is dependent on the applied magnetic field. The results of our efforts to characterize the relaxation of xenon are presented. The final section describes the solid-state variable-temperature (VT) one- and two-dimensional 13C cross polarization (CP)/magic angle spinning (MAS) NMR of Hf(η5-C5H5)21-C5H5)2, Zr

  7. Solid state {sup 31}P MAS NMR spectroscopy and conductivity measurements on NbOPO{sub 4} and H{sub 3}PO{sub 4} composite materials

    SciTech Connect

    Risskov Sørensen, Daniel; Nielsen, Ulla Gro; Skou, Eivind M.

    2014-11-15

    A systematic study of composite powders of niobium oxide phosphate (NbOPO{sub 4}) and phosphoric acid (H{sub 3}PO{sub 4}) has been performed in order to characterize the material's ability to perform as an electrolyte material in medium temperature fuel cells and electrolyzers. Powders of H{sub 3}PO{sub 4} contents between 13.1 and 74.2 M% were produced and characterized with powder X-ray diffraction, {sup 31}P MAS NMR and impedance spectroscopy. NMR revealed that a significant degree of dehydration and vaporization of H{sub 3}PO{sub 4} takes place above 200 °C, and increases with temperature. At 500 °C the NbOPO{sub 4} and H{sub 3}PO{sub 4} has reacted to form niobium pyrophosphate (Nb{sub 2}P{sub 4}O{sub 15}). Impedance spectroscopy showed an increase in conductivity with increasing acid concentration, whereas the conductivity decreased slightly with increasing temperature. The highest conductivity measured was 2.5·10{sup −3} S/cm for a sample containing 74.2 M% of H{sub 3}PO{sub 4}. Lastly, it was shown that NbOPO{sub 4} has no significant conductivity of its own. - Graphical abstract: Conductivity of NbOPO{sub 4}/H{sub 3}PO{sub 4} composites as a function of equivalent P{sub 2}O{sub 5} content. The conductivity is insignificant for pure NbOPO{sub 4}. - Highlights: • Composites have been made from NbOPO{sub 4} and H{sub 3}PO{sub 4}. • The composites composition has been investigated with solid state NMR. • The composites have shown clear signs of acid dehydration upon heating. • The conductivity of the composites increases for increasing acid content. • NbOPO{sub 4} has no significant conductivity of its own.

  8. Investigation of organic condensed phoshates: Synthesis and structural characterization by 31P MAS NMR and X-ray diffraction of the 3-phenylpropylamonium cyclohexaphosphate dihydrate

    NASA Astrophysics Data System (ADS)

    Hlel, F.; Thouvenot, R.; Smiri, L.

    2005-05-01

    Preparation, crystal structure and infra-red absorption spectra are reported for a new organic salt of the cyclohexaphosphate, [C6H5(CH2)3NH3]6P6O18 . 2 H2O. The new compound crystallizes in the triclinic system (P space group) with Z = 2 and the following unit cell dimensions: a = 10.528(3), b = 19.183(2), c = 9.839(3) Å, = 74.92(5), = 117.48(6) and = 99.90(5)°. The structure was solved by using 6709 independent reflections down to R value of 0.039. The ring anion exhibits internal symmetry. Its main geometrical features are those commonly observed in the atomic arrangements of cyclohexaphosphates. The three dimensional cohesion of this atomic arrangement is maintained through H-bonds between organic cations, water molecules and the external oxygen atoms of the P6O18-6 ring. The H-bond interactions induce local distortions of the ring leading to the existence of three different types of phosphate tetrahedra.Solid-state 31P magic-angle-spinning nuclear magnetic resonance (MAS NMR), performed at 162 MHz shows three isotropic resonances at -19.8, -22.6 and -24.5 ppm, confirming the non-equivalence of the three PO4 groups. They are characterized by different chemical shift tensor parameters, which are in agreement with the local geometrical features of the tetrahedra.

  9. Structural investigations of silicate-phosphate glasses containing MoO3 by FTIR, Raman and 31P MAS NMR spectroscopies

    NASA Astrophysics Data System (ADS)

    Szumera, Magdalena

    2014-09-01

    Molybdenum is a transition metal (refers to the “d” block of the periodic table) whose atom has an incomplete d sub-shell. It is known that in silicate glasses molybdenum may exist under four oxidation states: Mo6+, Mo5+, Mo4+ and Mo3+, simultaneously molybdenum cations, depending on their content in the glass network, may either be a glass forming component, or act as a modifier. The contemporary literature data show studies conducted mostly on the structure of silicate, phosphate, borate and borosilicate glasses containing molybdenum ions, but not silicate-phosphate glasses. Therefore, the author has undertaken detailed studies using FTIR, Raman and 31P MAS NMR techniques in order to examine the effect of MoO3 addition into the structure of silicate-phosphate glasses from SiO2sbnd P2O5sbnd K2Osbnd CaOsbnd MgO system. On the basis of obtained results it was concluded that molybdenum ions in the analysed glasses act as a modifier, which follows from the gradual breakage of oxygen bridges, i.e. Psbnd Osbnd P, Sisbnd Osbnd Si, and Sisbnd Osbnd P, and the following formation of connections such as Mo[MoO4]sbnd Osbnd Si and/or Mo[MoO4]sbnd Osbnd P. In summary, it is concluded that the increase of MoO3 content (up to 4.4 mol.%) in the structure of glasses of SiO2sbnd P2O5sbnd K2Osbnd MgOsbnd CaO system results in weakening of the structure and gradual increase of the degree of silico-oxygen and phosphor-oxygen frameworks depolymerisation.

  10. Structural investigations of silicate-phosphate glasses containing MoO3 by FTIR, Raman and 31P MAS NMR spectroscopies.

    PubMed

    Szumera, M

    2014-09-15

    Molybdenum is a transition metal (refers to the "d" block of the periodic table) whose atom has an incomplete d sub-shell. It is known that in silicate glasses molybdenum may exist under four oxidation states: Mo6+, Mo5+, Mo4+ and Mo3+, simultaneously molybdenum cations, depending on their content in the glass network, may either be a glass forming component, or act as a modifier. The contemporary literature data show studies conducted mostly on the structure of silicate, phosphate, borate and borosilicate glasses containing molybdenum ions, but not silicate-phosphate glasses. Therefore, the author has undertaken detailed studies using FTIR, Raman and 31P MAS NMR techniques in order to examine the effect of MoO3 addition into the structure of silicate-phosphate glasses from SiO2P2O5K2OCaOMgO system. On the basis of obtained results it was concluded that molybdenum ions in the analysed glasses act as a modifier, which follows from the gradual breakage of oxygen bridges, i.e. POP, SiOSi, and SiOP, and the following formation of connections such as Mo[MoO4]OSi and/or Mo[MoO4]OP. In summary, it is concluded that the increase of MoO3 content (up to 4.4 mol.%) in the structure of glasses of SiO2P2O5K2OMgOCaO system results in weakening of the structure and gradual increase of the degree of silico-oxygen and phosphor-oxygen frameworks depolymerisation.

  11. {sup 1}H and {sup 23}Na MAS NMR spectroscopy of cationic species in CO{sub 2} selective alkaline earth metal porous silicoaluminophosphates prepared via liquid and solid state ion exchange

    SciTech Connect

    Arevalo-Hidalgo, Ana G.; Dugar, Sneha; Fu, Riqiang; Hernandez-Maldonado, Arturo J.

    2012-07-15

    The location of extraframework cations in Sr{sup 2+} and Ba{sup 2+} ion-exchanged SAPO-34 was estimated by means of {sup 1}H and {sup 23}Na MAS NMR spectroscopy and spectral deconvolution. Incorporation of the alkaline earth metal cations onto the SAPO framework was achieved via liquid state ion exchange, coupled partial detemplation/solid-state ion exchange, and combination of both techniques. MAS NMR revealed that the level of ion exchange was limited by the presence of protons and sodium cations near hexagonal prisms (site SI), which are relatively difficult to exchange with the alkaline earth metal due to steric and charge repulsion criteria. In addition, the presence of ammonium cations in the supercages facilitated the exchange of otherwise tenacious hydrogen as corroborated by unit cell compositional data as well as enhanced CO{sub 2} adsorption at low partial pressures. The extraframework ammonium species were produced from partial detemplation of the structure-directing agent employed for the SAPO-34 synthesis, tetraethylammonium. - Graphical abstract: MAS NMR was used to elucidate the position the cationic species in alkaline earth metal exchanged silicoaluminophosphates. These species played a significant role during the ion exchange process and, therefore, the materials ultimate CO{sub 2} adsorption performance. Highlights: Black-Right-Pointing-Pointer Location of extraframework Sr{sup 2+} or Ba{sup 2+} cations was estimated by means of {sup 1}H and {sup 23}Na MAS NMR. Black-Right-Pointing-Pointer Level of Sr{sup 2+} or Ba{sup 2+} ion exchange was limited by the presence of protons and sodium cations. Black-Right-Pointing-Pointer Presence of ammonium cations in the supercages facilitated the exchange. Black-Right-Pointing-Pointer Sr{sup 2+} and Ba{sup 2+} ion exchanged SAPOs are outstanding CO{sub 2} adsorbents.

  12. Investigation of relative metabolic changes in the organs and plasma of rats exposed to X-ray radiation using HR-MAS (1)H NMR and solution (1)H NMR.

    PubMed

    Jang, Won Gyo; Park, Ju Yeon; Lee, Jueun; Bang, Eunjung; Kim, So Ra; Lee, Eun Kyeong; Yun, Hyun Jin; Kang, Chang-Mo; Hwang, Geum-Sook

    2016-04-01

    Excess exposure to ionizing radiation generates reactive oxygen species and increases the cellular inflammatory response by modifying various metabolic pathways. However, an investigation of metabolic perturbations and organ-specific responses based on the amount of radiation during the acute phase has not been conducted. In this study, high-resolution magic-angle-spinning (HR-MAS) NMR and solution NMR-based metabolic profiling were used to investigate dose-dependent metabolic changes in multiple organs and tissues--including the jejunum, spleen, liver, and plasma--of rats exposed to X-ray radiation. The organs, tissues, and blood samples were obtained 24, 48, and 72 h after exposure to low-dose (2 Gy) and high-dose (6 Gy) X-ray radiation and subjected to metabolite profiling and multivariate analyses. The results showed the time course of the metabolic responses, and many significant changes were detected in the high-dose compared with the low-dose group. Metabolites with antioxidant properties showed acute responses in the jejunum and spleen after radiation exposure. The levels of metabolites related to lipid and protein metabolism were decreased in the jejunum. In addition, amino acid levels increased consistently at all post-irradiation time points as a consequence of activated protein breakdown. Consistent with these changes, plasma levels of tricarboxylic acid cycle intermediate metabolites decreased. The liver did not appear to undergo remarkable metabolic changes after radiation exposure. These results may provide insight into the major metabolic perturbations and mechanisms of the biological systems in response to pathophysiological damage caused by X-ray radiation.

  13. Modeling Ti/Ge Distribution in LiTi2-xGex(PO4)3 NASICON Series by (31)P MAS NMR and First-Principles DFT Calculations.

    PubMed

    Diez-Gómez, Virginia; Arbi, Kamel; Sanz, Jesús

    2016-08-03

    Ti/Ge distribution in rhombohedral LiTi2-xGex(PO4)3 NASICON series has been analyzed by (31)P magic-angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy and first-principles density functional theory (DFT) calculations. Nuclear magnetic resonance is an excellent probe to follow Ti/Ge disorder, as it is sensitive to the atomic scale environment without long-range periodicity requirements. In the samples considered here, PO4 units are surrounded by four Ti/Ge octahedra, and then, five different components ascribed to P(OTi)4, P(OTi)3(OGe), P(OTi)2(OGe)2, P(OTi)(OGe)3, and P(OGe)4 environments are expected in (31)P MAS NMR spectra of R3̅c NASICON samples. However, (31)P MAS NMR spectra of analyzed series display a higher number of signals, suggesting that, although the overall symmetry remains R3̅c, partial substitution causes a local decrement in symmetry. With the aid of first-principles DFT calculations, 10 detected (31)P NMR signals have been assigned to different Ti4-nGen arrangements in the R3 subgroup symmetry. In this assignment, the influence of octahedra of the same or different R2(PO4)3 structural units has been considered. The influence of bond distances, angles and atom charges on (31)P NMR chemical shieldings has been discussed. Simulation of the LiTi2-xGex(PO4)3 series suggests that detection of 10 P environments is mainly due to the existence of two oxygen types, O1 and O2, whose charges are differently affected by Ge and Ti occupation of octahedra. From the quantitative analysis of detected components, a random Ti/Ge distribution has been deduced in next nearest neighbor (NNN) sites that surround tetrahedral PO4 units. This random distribution was supported by XRD data displaying Vegard's law.

  14. Investigating the Surface Structure of γ-Al 2 O 3 Supported WO X Catalysts by High Field 27 Al MAS NMR and Electronic Structure Calculations

    SciTech Connect

    Wan, Chuan; Hu, Mary Y.; Jaegers, Nicholas R.; Shi, Dachuan; Wang, Huamin; Gao, Feng; Qin, Zhaohai; Wang, Yong; Hu, Jian Zhi

    2016-10-13

    The metal-support interaction in γ-Al2O3 supported WOX catalysts is investigated by a combination of high field quantitative single pulse (SP) 27Al MAS NMR spectroscopy, 2D MQMAS, 1H-27Al CP/MAS, and electronic structure calculations. NMR allows the observation of at least seven different Al sites, including a pentahedral Al site, three different tetrahedral Al sites, and three octahedral Al sites. It is found that the penta-coordinated Al (AlP) site density decreases monotonically with an increased WOX loading while the octahedral Al (AlO) site density increases concurrently. This suggests that the Alp sites are the preferred surface anchoring positions for the WOX species. Importantly, the AlP site isotropic chemical shift observed for the unsupported γ-Al2O3 at about 38 ppm migrates into the octahedral region with a new isotropic chemical shift value appearing near 7 ppm when the Alp site is anchored by WOX species. Density functional theory (DFT) computational modeling of the NMR parameters on proposed cluster models is carried out to accurately interpret the dramatic chemical shift changes from which the detailed anchoring mechanisms are obtained. It is found that tungsten dimers and monomers are the preferred supported surface species on γ-Al2O3, wherein one monomeric and several dimeric structures are identified as the most likely surface anchoring structures.

  15. PEX11B — EDRN Public Portal

    Cancer.gov

    PEX11B, or peroxisomal biogenesis factor 11 beta, is involved in peroxisomal proliferation and interacts with PEX19. PEX11B is located in the peroxisomal membrane and is thought to regulate peroxisome division by recruiting the dynamin-related GTPase DNM1L to the peroxisomal membrane.

  16. Probing Oxide-Ion Mobility in the Mixed Ionic-Electronic Conductor La2NiO4+δ by Solid-State (17)O MAS NMR Spectroscopy.

    PubMed

    Halat, David M; Dervişoğlu, Rıza; Kim, Gunwoo; Dunstan, Matthew T; Blanc, Frédéric; Middlemiss, Derek S; Grey, Clare P

    2016-09-14

    While solid-state NMR spectroscopic techniques have helped clarify the local structure and dynamics of ionic conductors, similar studies of mixed ionic-electronic conductors (MIECs) have been hampered by the paramagnetic behavior of these systems. Here we report high-resolution (17)O (I = 5/2) solid-state NMR spectra of the mixed-conducting solid oxide fuel cell (SOFC) cathode material La2NiO4+δ, a paramagnetic transition-metal oxide. Three distinct oxygen environments (equatorial, axial, and interstitial) can be assigned on the basis of hyperfine (Fermi contact) shifts and quadrupolar nutation behavior, aided by results from periodic DFT calculations. Distinct structural distortions among the axial sites, arising from the nonstoichiometric incorporation of interstitial oxygen, can be resolved by advanced magic angle turning and phase-adjusted sideband separation (MATPASS) NMR experiments. Finally, variable-temperature spectra reveal the onset of rapid interstitial oxide motion and exchange with axial sites at ∼130 °C, associated with the reported orthorhombic-to-tetragonal phase transition of La2NiO4+δ. From the variable-temperature spectra, we develop a model of oxide-ion dynamics on the spectral time scale that accounts for motional differences of all distinct oxygen sites. Though we treat La2NiO4+δ as a model system for a combined paramagnetic (17)O NMR and DFT methodology, the approach presented herein should prove applicable to MIECs and other functionally important paramagnetic oxides.

  17. Probing Oxide-Ion Mobility in the Mixed Ionic–Electronic Conductor La2NiO4+δ by Solid-State 17O MAS NMR Spectroscopy

    PubMed Central

    2016-01-01

    While solid-state NMR spectroscopic techniques have helped clarify the local structure and dynamics of ionic conductors, similar studies of mixed ionic–electronic conductors (MIECs) have been hampered by the paramagnetic behavior of these systems. Here we report high-resolution 17O (I = 5/2) solid-state NMR spectra of the mixed-conducting solid oxide fuel cell (SOFC) cathode material La2NiO4+δ, a paramagnetic transition-metal oxide. Three distinct oxygen environments (equatorial, axial, and interstitial) can be assigned on the basis of hyperfine (Fermi contact) shifts and quadrupolar nutation behavior, aided by results from periodic DFT calculations. Distinct structural distortions among the axial sites, arising from the nonstoichiometric incorporation of interstitial oxygen, can be resolved by advanced magic angle turning and phase-adjusted sideband separation (MATPASS) NMR experiments. Finally, variable-temperature spectra reveal the onset of rapid interstitial oxide motion and exchange with axial sites at ∼130 °C, associated with the reported orthorhombic-to-tetragonal phase transition of La2NiO4+δ. From the variable-temperature spectra, we develop a model of oxide-ion dynamics on the spectral time scale that accounts for motional differences of all distinct oxygen sites. Though we treat La2NiO4+δ as a model system for a combined paramagnetic 17O NMR and DFT methodology, the approach presented herein should prove applicable to MIECs and other functionally important paramagnetic oxides. PMID:27538437

  18. 13C and 15N—Chemical Shift Anisotropy of Ampicillin and Penicillin-V Studied by 2D-PASS and CP/MAS NMR

    NASA Astrophysics Data System (ADS)

    Antzutkin, Oleg N.; Lee, Young K.; Levitt, Malcolm H.

    1998-11-01

    The principal values of the chemical shift tensors of all13C and15N sites in two antibiotics, ampicillin and penicillin-V, were determined by 2-dimensionalphaseadjustedspinningsideband (2D-PASS) and conventional CP/MAS experiments. The13C and15N chemical shift anisotropies (CSA), and their confidence limits, were evaluated using a Mathematica program. The CSA values suggest a revised assignment of the 2-methyl13C sites in the case of ampicillin. We speculate on a relationship between the chemical shift principal values of many of the13C and15N sites and the β-lactam ring conformation.

  19. The Local Structural State of Aluminosilicate Garnet Solid Solutions: An Investigation of Grospydite Garnet from the Roberts Victor Kimberlite Using Paramagnetically Shifted 27Al and 29Si MAS NMR Resonances

    NASA Astrophysics Data System (ADS)

    Geiger, C. A.; Palke, A. C.; Stebbins, J. F.

    2014-12-01

    Most rock-forming silicates are substitutional solid solutions. Over the years extensive research has been done to determine their structural and crystal chemical properties. Here, the distribution of cations, or order-disorder behavior, is of central importance. In the case of aluminosilicate garnet solid solutions (X3Al2Si3O12 with X = Mg, Fe2+, Mn2+ and Ca) it has been shown that both synthetic and natural crystals have random long-range X-cation disorder in space group Ia-3d, as given by X-ray single-crystal diffraction measurements. However, the structural state of natural garnets at the local scale is not known. Garnet from a grospydite xenolith from the Roberts Victor kimberlite, South Africa, was studied by 27Al and 29Si MAS NMR spectroscopy. The research thrust was placed on measuring and analyzing paramagnetically shifted resonances to determine the local (short range) structural state of the X-cations in a grossular-rich ternary aluminosilicate garnet solid solution. The garnet crystals are compositionally homogeneous based on microprobe analysis, showing no measurable zoning, and have the formula Grs46.7Prp30.0Alm23.3. The garnet is cubic with the standard garnet space group Ia-3d. The 27Al MAS NMR spectrum shows a very broad asymmetric resonance located between about 100 and -50 ppm. It consists of a number of individual overlapping paramagnetically shifted resonances, which are difficult to analyze quantitatively. The 29Si MAS NMR spectrum, showing better resolution, has two observable resonances termed S0 and S4. S0 is located between about -60 ppm and -160 ppm and S4 is centered at roughly 95 ppm. Both S0 and S4 are composite resonances in nature containing many overlapping individual peaks. S0 contains information on local cation configurations whereby an isolated SiO4 group in the garnet structure does not have an edge-shared Fe2+-containing dodecahedron. S4 involves local configurations where there is one edge-shared dodecahedron containing Fe2

  20. Efficient polarization transfer between spin-1/2 and ¹⁴N nuclei in solid-state MAS NMR spectroscopy.

    PubMed

    Basse, Kristoffer; Jain, Sheetal Kumar; Bakharev, Oleg; Nielsen, Niels Chr

    2014-07-01

    Polarization transfer between spin-1/2 nuclei and quadrupolar spin-1 nuclei such as (14)N in solid-state NMR is severely challenged by the typical presence of large quadrupole coupling interactions. This has effectively prevented the use of the abundant (14)N spin as a probe to structural information and its use as an element in multi-dimensional solid-state NMR correlation experiments for assignment and structural characterization. In turn, this has been a contributing factor to the extensive use of isotope labeling in biological solid-state NMR, where (14)N is replaced with (15)N. The alternative strategy of using the abundant (14)N spins calls for methods enabling efficient polarization transfer between (14)N and its binding partners. This work demonstrates that the recently introduced (RESPIRATION)CP transfer method can be optimized to achieve efficient (1)H ↔(14)N polarization transfer under magic angle spinning conditions. The method is demonstrated numerically and experimentally on powder samples of NH4NO3 and L-alanine.

  1. Exploring electrolyte organization in supercapacitor electrodes with solid-state NMR

    NASA Astrophysics Data System (ADS)

    Deschamps, Michaël; Gilbert, Edouard; Azais, Philippe; Raymundo-Piñero, Encarnación; Ammar, Mohammed Ramzi; Simon, Patrick; Massiot, Dominique; Béguin, François

    2013-04-01

    Supercapacitors are electrochemical energy-storage devices that exploit the electrostatic interaction between high-surface-area nanoporous electrodes and electrolyte ions. Insight into the molecular mechanisms at work inside supercapacitor carbon electrodes is obtained with 13C and 11B ex situ magic-angle spinning nuclear magnetic resonance (MAS-NMR). In activated carbons soaked with an electrolyte solution, two distinct adsorption sites are detected by NMR, both undergoing chemical exchange with the free electrolyte molecules. On charging, anions are substituted by cations in the negative carbon electrode and cations by anions in the positive electrode, and their proportions in each electrode are quantified by NMR. Moreover, acetonitrile molecules are expelled from the adsorption sites at the negative electrode alone. Two nanoporous carbon materials were tested, with different nanotexture orders (using Raman and 13C MAS-NMR spectroscopies), and the more disordered carbon shows a better capacitance and a better tolerance to high voltages.

  2. Carbonation of C–S–H and C–A–S–H samples studied by {sup 13}C, {sup 27}Al and {sup 29}Si MAS NMR spectroscopy

    SciTech Connect

    Sevelsted, Tine F.; Skibsted, Jørgen

    2015-05-15

    Synthesized calcium silicate hydrate (C–S–H) samples with Ca/Si ratios of 0.66, 1.0, and 1.5 have been exposed to atmospheric CO{sub 2} at room temperature and high relative humidity and studied after one to 12 weeks. {sup 29}Si NMR reveals that the decomposition of C–S–H caused by carbonation involves two steps and that the decomposition rate decreases with increasing Ca/Si ratio. The first step is a gradual decalcification of the C–S–H where calcium is removed from the interlayer and defect sites in the silicate chains until Ca/Si = 0.67 is reached, ideally corresponding to infinite silicate chains. In the seconds step, calcium from the principal layers is consumed, resulting in the final decomposition of the C–S–H and the formation of an amorphous silica phase composed of Q{sup 3} and Q{sup 4} silicate tetrahedra. The amount of solid carbonates and of carbonate ions in a hydrous environment increases with increasing Ca/Si ratio for the C–S–H, as shown by {sup 13}C NMR. For C–A–S–H samples with Ca/Si = 1.0 and 1.5, {sup 27}Al NMR demonstrates that all aluminium sites associated with the C–S–H are consumed during the carbonation reactions and incorporated mainly as tetrahedral Al(–OSi){sub 4} units in the amorphous silica phase. A small amount of penta-coordinated Al sites has also been identified in the silica phase.

  3. An infrared and 1H MAS NMR investigation of strong hydrogen bonding in ussingite, Na2AlSi3O8(OH)

    NASA Astrophysics Data System (ADS)

    Johnson, E. A.; Rossman, G. R.

    The mineral ussingite, Na2AlSi3O8(OH), an ``interrupted'' tectosilicate, has strong hydrogen bonding between OH and the other nonbridging oxygen atom in the structure. Infrared spectra contain a strongly polarized, very broad OH-stretching band with an ill-defined maximum between 1500 and 1800 cm-1, and a possible OH librational bending mode at 1295 cm-1. The IR spectra confirm the orientation of the OH vector within the triclinic unit cell as determined from X-ray refinement (Rossi et al. 1974). There are three distinct bands in the 1H NMR spectrum of ussingite: a predominant band at 13.5 ppm (TMS) representing 90% of the structural hydrogen, a second band at 15.9 ppm corresponding to 8% of the protons, and a third band at 11.0 ppm accounting for the remaining 2% of structural hydrogen. From the correlation between hydrogen bond length and 1H NMR chemical shift (Sternberg and Brunner 1994), the predominant hydrogen bond length (H...O) was calculated to be 1.49 Å, in comparison to the hydrogen bond length determined from X-ray refinement (1.54 Å). The population of protons at 15.9 ppm is consistent with 5-8% Al-Si disorder. Although the ussingite crystal structure and composition are similar to those of low albite, the bonding environment of OH in low albite and other feldspars, as characterized through IR and 1H NMR, is fundamentally different from the strong hydrogen bonding found in ussingite.

  4. Spin-transfer pathways in paramagnetic lithium transition-metal phosphates from combined broadband isotropic solid-state MAS NMR spectroscopy and DFT calculations.

    PubMed

    Clément, Raphaële J; Pell, Andrew J; Middlemiss, Derek S; Strobridge, Fiona C; Miller, Joel K; Whittingham, M Stanley; Emsley, Lyndon; Grey, Clare P; Pintacuda, Guido

    2012-10-17

    Substituted lithium transition-metal (TM) phosphate LiFe(x)Mn(1-x)PO(4) materials with olivine-type structures are among the most promising next generation lithium ion battery cathodes. However, a complete atomic-level description of the structure of such phases is not yet available. Here, a combined experimental and theoretical approach to the detailed assignment of the (31)P NMR spectra of the LiFe(x)Mn(1-x)PO(4) (x = 0, 0.25, 0.5, 0.75, 1) pure and mixed TM phosphates is developed and applied. Key to the present work is the development of a new NMR experiment enabling the characterization of complex paramagnetic materials via the complete separation of the individual isotropic chemical shifts, along with solid-state hybrid DFT calculations providing the separate hyperfine contributions of all distinct Mn-O-P and Fe-O-P bond pathways. The NMR experiment, referred to as aMAT, makes use of short high-powered adiabatic pulses (SHAPs), which can achieve 100% inversion over a range of isotropic shifts on the order of 1 MHz and with anisotropies greater than 100 kHz. In addition to complete spectral assignments of the mixed phases, the present study provides a detailed insight into the differences in electronic structure driving the variations in hyperfine parameters across the range of materials. A simple model delimiting the effects of distortions due to Mn/Fe substitution is also proposed and applied. The combined approach has clear future applications to TM-bearing battery cathode phases in particular and for the understanding of complex paramagnetic phases in general.

  5. Interface Induced Growth and Transformation of Polymer-Conjugated Proto-Crystalline Phases in Aluminosilicate Hybrids: A Multiple-Quantum (23)Na-(23)Na MAS NMR Correlation Spectroscopy Study.

    PubMed

    Brus, Jiri; Kobera, Libor; Urbanova, Martina; Doušová, Barbora; Lhotka, Miloslav; Koloušek, David; Kotek, Jiří; Čuba, Pavel; Czernek, Jiri; Dědeček, Jiří

    2016-03-22

    Nanostructured materials typically offer enhanced physicochemical properties because of their large interfacial area. In this contribution, we present a comprehensive structural characterization of aluminosilicate hybrids with polymer-conjugated nanosized zeolites specifically grown at the organic-inorganic interface. The inorganic amorphous Al-O-Si framework is formed by alkali-activated low-temperature transformation of metakaoline, whereas simultaneous copolymerization of organic comonomers creates a secondary epoxide network covalently bound to the aluminosilicate matrix. This secondary epoxide phase not only enhances the mechanical integrity of the resulting hybrids but also introduces additional binding sites accessible for compensating negative charge on the aluminosilicate framework. This way, the polymer network initiates growth and subsequent transformation of protocrystalline short-range ordered zeolite domains that are located at the organic-inorganic interface. By applying an experimental approach based on 2D (23)Na-(23)Na double-quantum (DQ) MAS NMR spectroscopy, we discovered multiple sodium binding sites in these protocrystalline domains, in which immobilized Na(+) ions form pairs or small clusters. It is further demonstrated that these sites, the local geometry of which allows for the pairing of sodium ions, are preferentially occupied by Pb(2+) ions during the ion exchange. The proposed synthesis protocol thus allows for the preparation of a novel type of geopolymer hybrids with polymer-conjugated zeolite phases suitable for capturing and storage of metal cations. The demonstrated (23)Na-(23)Na DQ MAS NMR combined with DFT calculations represents a suitable approach for understanding the role of Na(+) ions in aluminositicate solids and related inorganic-organic hybrids, particularly their specific arrangement and clustering at interfacial areas.

  6. Stoichiometric compounds of magnesium dichloride with ethanol for the supported Ziegler-Natta catalysis: first recognition and multidimensional MAS NMR study.

    PubMed

    Sozzani, Piero; Bracco, Silvia; Comotti, Angiolina; Simonutti, Roberto; Camurati, Isabella

    2003-10-22

    Ethanol associates easily with MgCl(2) to form adducts of complex architecture, but until now available characterization methods have failed to identify the pure stoichiometric compounds and their structures. To remedy this, we set about applying homonuclear and heteronuclear 2D correlated solid-state NMR spectroscopy to identify the pure compounds and the ethanol-to-magnesium coordination pattern. High spinning speed and Lee-Goldburg sequences were able to reduce the hydrogen spin-diffusion and homonuclear coupling in the crystalline solid, thus achieving high resolution also in the hydrogen domain. On this basis, the pure adducts, of interest as catalyst supports for Ziegler-Natta polymerization, were isolated for the first time. Magnesium coordination sites with given numbers of ligands and their multiplicity in the crystal cells were determined in the new-found stoichiometric complexes. Variable temperature and 2D carbon-carbon exchange NMR, as well as relaxation times in the fast motion regime, revealed the disordering phenomena generated by ethanol dynamics in the crystal. Decoding the intriguing polymorphism of the precursors permits to trace the genealogy of tailored MgCl(2) titanate granules, active as highly productive catalysts for the stereospecific polymerization of olefins.

  7. Insight into hydrogen bonding of uranyl hydroxide layers and capsules by use of 1H magic-angle spinning NMR spectroscopy [Insight into the hydrogen bonding for uranyl hydroxides using 1H MAS NMR spectroscopy

    SciTech Connect

    Alam, Todd M.; Liao, Zuolei; Nyman, May; Yates, Jonathan

    2016-04-27

    Solid-state 1H magic-angle spinning (MAS) NMR was used to investigate local proton environments in anhydrous [UO2(OH)2] (α-UOH) and hydrated uranyl hydroxide [(UO2)4O(OH)6·5H2O (metaschoepite). For the metaschoepite material, proton resonances of the μ2-OH hydroxyl and interlayer waters were resolved, with two-dimensional (2D) double-quantum (DQ) 1H–1H NMR correlation experiments revealing strong dipolar interactions between these different proton species. The experimental NMR results were combined with first-principles CASTEP GIPAW (gauge including projector-augmented wave) chemical shift calculations to develop correlations between hydrogen-bond strength and observed 1H NMR chemical shifts. Furthermore, these NMR correlations allowed characterization of local hydrogen-bond environments in uranyl U24 capsules and of changes in hydrogen bonding that occurred during thermal dehydration of metaschoepite.

  8. Proton-detected 3D (15)N/(1)H/(1)H isotropic/anisotropic/isotropic chemical shift correlation solid-state NMR at 70kHz MAS.

    PubMed

    Pandey, Manoj Kumar; Yarava, Jayasubba Reddy; Zhang, Rongchun; Ramamoorthy, Ayyalusamy; Nishiyama, Yusuke

    2016-01-01

    Chemical shift anisotropy (CSA) tensors offer a wealth of information for structural and dynamics studies of a variety of chemical and biological systems. In particular, CSA of amide protons can provide piercing insights into hydrogen-bonding interactions that vary with the backbone conformation of a protein and dynamics. However, the narrow span of amide proton resonances makes it very difficult to measure (1)H CSAs of proteins even by using the recently proposed 2D (1)H/(1)H anisotropic/isotropic chemical shift (CSA/CS) correlation technique. Such difficulties due to overlapping proton resonances can in general be overcome by utilizing the broad span of isotropic chemical shifts of low-gamma nuclei like (15)N. In this context, we demonstrate a proton-detected 3D (15)N/(1)H/(1)H CS/CSA/CS correlation experiment at fast MAS frequency (70kHz) to measure (1)H CSA values of unresolved amide protons of N-acetyl-(15)N-l-valyl-(15)N-l-leucine (NAVL).

  9. Magic angle Lee-Goldburg frequency offset irradiation improves the efficiency and selectivity of SPECIFIC-CP in triple-resonance MAS solid-state NMR.

    PubMed

    Wu, Chin H; De Angelis, Anna A; Opella, Stanley J

    2014-09-01

    The efficiency and selectivity of SPECIFIC-CP, a widely used method for selective double cross-polarization in triple-resonance magic angle spinning solid-state NMR, is improved by performing the tangential-shaped (13)C irradiation at an offset frequency that meets the Lee-Goldburg condition (LG-SPECIFIC-CP). This is demonstrated on polycrystalline samples of uniformly (13)C, (15)N labeled N-acetyl-leucine and N-formyl-Met-Leu-Phe-OH (MLF) at 700MHz and 900MHz (1)H resonance frequencies, respectively. For the single (13)Cα of N-acetyl-leucine, relative to conventional broad band cross-polarization, the SPECIFIC-CP signal has 47% of the intensity. Notably, the LG-SPECIFIC-CP signal has 72% of the intensity, essentially the theoretical maximum. There were no other changes in the experimental parameters. The three (13)Cα signals in MLF show some variation in intensities, reflecting the relatively narrow bandwidth of a frequency-offset procedure, and pointing to future developments for this class of experiment.

  10. MAS NMR Study of the Metastable Solid Solutions Found in the LiFePO4/FePO4 System

    SciTech Connect

    Cabana, Jordi; Shirakawa, Junichi; Chen, Guoying; Richardson, Thomas; Grey, Clare P.

    2009-10-09

    Li and 3IP NMR experiments were conducted on a series of single- or two-phase samples in the LiFePCvFePCM system with different overall lithium contents, and containing the two end-members and/or two metastable solid solution hases, Lio.6FeP04 or Lio.34FeP04. These experiments were carried out at different temperatures in order to search for vacancy/charge ordering and ion/electron mobility in the metastable phases. Evidence for Li+-Fe2+ interactions was bserved for both Lio.6FeP04 and Lio.34FePC>4. The strength of this interaction leads to the formation of LiFePCvlike clusters in the latter, as shown by the room temperature data. Different motional processes are proposed to exist as the temperature is increased and various scenarios are discussed. While concerted lithium-electron hopping and/or correlations explains the data below 125C, evidence for some uncorrelated motion is found at higher temperatures, together with the onset of phase mixing.

  11. The Amblygonite (LiAlPO{sub 4}F)-Montebrasite (LiAlPO{sub 4}OH) Solid Solution: A Combined powder and single-crystal neutron diffraction and solid-state {sup 6}Li MAS, CP MAS, and REDOR NMR study

    SciTech Connect

    Groat, Lee A.; Chakoumakos, Bryan C.; Brouwer, Darren H.; Hoffman, Christina M.; Fyfe, Colin A.; Morell, Heiko; Schultz, Arthur J.

    2003-01-01

    The amblygonite-montebrasite series of minerals, common constituents of granitic pegmatites and topaz-bearing granites, show complete solid solution with ideal composition LiAlPO{sub 4}(F, OH). These compounds are ideal for studying F {leftrightarrow} OH solid solution in minerals because natural members of the series generally show little deviation from the ideal composition. In this study, we used powder and single-crystal neutron diffraction and solid-state {sup 6}Li MAS, CP MAS, and REDOR NMR techniques to study the effect of F {leftrightarrow} OH substitution on the series. Lattice parameters refined from single-crystal neutron diffraction data show increasing b and decreasing a, c, and V with increasing F/(F + OH). The volume is highest for the OH end-member because of the presence of an additional atom (H). The a and c parameters decrease with increasing F/(F + OH) because the O-H vector is close to the a-c plane and the Al-OH/F vectors are approximately parallel to c. Lattice parameters refined from neutron powder diffraction patterns collected at lower T show that thermal contraction increases with F/(F + OH), presumably because the F anion takes up less space than the OH molecule. The results show that the OH/F position is always fully occupied. The H displacement ellipsoid shows little change with occupancy, which obviously corresponds negatively with increasing F/(F + OH). However, the Li displacement ellipsoid becomes extremely large and anisotropic with increasing F fraction. Most of the distortion is associated with the U{sub 3} eigenvalue, which lies between the c and c* directions. U{sub eq} values corresponding to the Li atom show a greater reduction with decreasing temperature than the other atoms. The temperature dependence of Li is the same regardless of F content. Even when extrapolated to absolute zero the Li displacement ellipsoid is very large, which implies a large static disorder.

  12. Lithium Ion Mobility in Lithium Phosphidosilicates: Crystal Structure, (7) Li, (29) Si, and (31) P MAS NMR Spectroscopy, and Impedance Spectroscopy of Li8 SiP4 and Li2 SiP2.

    PubMed

    Toffoletti, Lorenzo; Kirchhain, Holger; Landesfeind, Johannes; Klein, Wilhelm; van Wüllen, Leo; Gasteiger, Hubert A; Fässler, Thomas F

    2016-12-05

    The need to improve electrodes and Li-ion conducting materials for rechargeable all-solid-state batteries has drawn enhanced attention to the investigation of lithium-rich compounds. The study of the ternary system Li-Si-P revealed a series of new compounds, two of which, Li8 SiP4 and Li2 SiP2 , are presented. Both phases represent members of a new family of Li ion conductors that display Li ion conductivity in the range from 1.15(7)×10(-6) Scm(-1) at 0 °C to 1.2(2)×10(-4) Scm(-1) at 75 °C (Li8 SiP4 ) and from 6.1(7)×10(-8) Scm(-1) at 0 °C to 6(1)×10(-6) Scm(-1) at 75 °C (Li2 SiP2 ), as determined by impedance measurements. Temperature-dependent solid-state (7) Li NMR spectroscopy revealed low activation energies of about 36 kJ mol(-1) for Li8 SiP4 and about 47 kJ mol(-1) for Li2 SiP2 . Both compounds were structurally characterized by X-ray diffraction analysis (single crystal and powder methods) and by (7) Li, (29) Si, and (31) P MAS NMR spectroscopy. Both phases consist of tetrahedral SiP4 anions and Li counterions. Li8 SiP4 contains isolated SiP4 units surrounded by Li atoms, while Li2 SiP2 comprises a three-dimensional network based on corner-sharing SiP4 tetrahedra, with the Li ions located in cavities and channels.

  13. (29)Si, (47)Ti, (49)Ti and (195)Pt solid state MAS NMR spectroscopic investigations of ternary silicides TPtSi, germanides TPtGe (T = Ti, Zr, Hf) and stannide TiPtSn.

    PubMed

    Benndorf, Christopher; Eckert, Hellmut; Pöttgen, Rainer

    2016-05-10

    Eight ternary tetrelides TPtX (T = Ti, Zr, Hf; X = Si, Ge, Sn) were synthesized from the elements by arc-melting and subsequent annealing. TiPtSi, ZrPtSi, ZrPtGe, HfPtSi and HfPtGe crystallize with the orthorhombic TiNiSi type structure, in the space group Pnma. The structures of HfPtSi (a = 654.44(9), b = 387.97(6), c = 750.0(1) pm, wR2 = 0.0592, 411 F(2) values, 20 variables) and HfPtGe (a = 660.36(7), b = 395.18(4), c = 763.05(8) pm, wR2 = 0.0495, 430 F(2) values, 20 variables) were refined from single crystal X-ray diffractometer data. TiPtSn adopts the cubic MgAgAs type. TiPtGe is dimorphic with a TiNiSi type high-temperature modification which transforms to cubic LT-TiPtGe (MgAgAs type). All phases were investigated by high resolution (29)Si, (47)Ti, (49)Ti and (195)Pt solid state MAS NMR spectroscopy. In the cubic compounds, the (47/49)Ti NMR signals are easily detected owing to the absence of quadrupolar broadening effects. The (195)Pt resonances of the orthorhombic compounds are characterized by strongly negative isotropic Knight shifts and large Knight shift anisotropies, whereas positive isotropic Knight shifts and no anisotropies are observed for the cubic compounds. These results indicate that the phase transition in TiPtGe is associated with dramatic changes in the electronic properties. Within each group of isotypic compounds the isotropic (29)Si, (47/49)Ti and (195)Pt Knight shifts show systematic dependences on the transition metal or tetrel atomic number, suggesting that the numerical values are influenced by the electronegativities of the metallic (or metalloid) neighbours.

  14. Characterization of polysulfone and polysulfone/vanillin microcapsules by 1H NMR spectroscopy, solid-state 13C CP/MAS-NMR spectroscopy, and N2 adsorption-desorption analyses.

    PubMed

    Peña, Brisa; de Ménorval, Louis-Charles; Garcia-Valls, Ricard; Gumí, Tània

    2011-11-01

    Textile detergent and softener industries have incorporated perfume microencapsulation technology to improve their products. Perfume encapsulation allows perfume protection until use and provides a long-lasting fragrance release. But, certain industrial microcapsules show low encapsulation capacity and low material stability. Polysulfone capsules have been already proposed to solve these drawbacks. Among them, PSf/Vanillin capsules were considered as a desirable system. They present both good material stability and high encapsulation capacity. However, several factors such as the final location of the perfume in the polymeric matrix, the aggregation state that it has in the capsule and its interaction with the capsule components have not been studied yet. These factors can provide vast information about the capsule performance and its improvement. With the aim to characterize these parameters, the physical and chemical properties of PSf/Vanillin capsules have been investigated by nuclear magnetic resonance (NMR) spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and N(2) adsorption-desorption measurements. AFM micrograph and N(2) isotherms confirm that the presence of vanillin modify the physical structure of PSf/Vanillin microcapsules as it is trapped in the capsule porosity. NMR results show that vanillin is present in solid state in PSf/Vanillin microcapsules.

  15. Characterization of white Portland cement hydration and the C-S-H structure in the presence of sodium aluminate by {sup 27}Al and {sup 29}Si MAS NMR spectroscopy

    SciTech Connect

    Andersen, Morten Daugaard; Jakobsen, Hans J.; Skibsted, Joergen

    2004-05-01

    The effects of hydrating a white Portland cement (wPc) in 0.30 and 0.50 M solutions of sodium aluminate (NaAlO{sub 2}) at 5 and 20 deg. C are investigated by {sup 27}Al and {sup 29}Si magic-angle spinning (MAS) NMR spectroscopy. It is demonstrated that NaAlO{sub 2} accelerates the hydration of alite and belite and results in calcium-silicate-hydrate (C-S-H) phases with longer average chain lengths of SiO{sub 4}/AlO{sub 4} tetrahedra. The C-S-H phases are investigated in detail and it is shown that the Al/Si ratio for the chains of tetrahedra is quite constant during the time studied for the hydration (6 h to 2 years) but increases for higher concentration of the NaAlO{sub 2} solution. The average chain lengths of 'pure' silicate and SiO{sub 4}/AlO{sub 4} tetrahedra demonstrate that Al acts as a linker for the silicate chains, thereby producing aluminosilicate chains with longer average chain lengths. Finally, it is shown that NaAlO{sub 2} reduces the quantity of ettringite and results in larger quantities of monosulfate and a calcium aluminate hydrate phase.

  16. Combined MAS NMR and X-ray powder diffraction structural characterization of hydrofluorocarbon-134 adsorbed on zeolite NaY: Observation of cation migration and strong sorbate-cation interactions

    SciTech Connect

    Grey, C.P.; Poshni, F.I.; Gualtieri, A.F.; Norby, P. |; Hanson, J.C.; Corbin, D.R.

    1997-02-26

    {sup 23}Na MAS NMR and synchrotron X-ray powder diffraction methods have been used to study the binding of hydrofluorocarbon-134 (HFC-134, CF{sub 2}HCF{sub 2}H) in zeolite NaY. A contraction of the volume of the unit cell is observed on gas adsorption, and the interaction of HFC-134 with the extraframework sodium cations is so strong that extraframework sodium cations in the sodalite cages (site I`) migrate into the supercages. These sodium cations are found on positions close to the site III` positions of zeolite NaX. Both ends of the HFC molecules are bound sodium cations, the HFC molecule bridging the site II and III` cations in the supercages. The strong cation-HFC interaction results in a considerable displacement of the sodium site II cation along the [111] direction into the supercage and an increase in the T-O-T bond angle for the three oxygen atoms coordinated to this cation. A decrease in the {sup 23}Na quadrupole coupling constant on HFC adsorption from 4.4 to less than 2.8 MHz, for the sodium cations originally located in the sodalite cages (site I`), is consistent with the sodium cation migrations. 26 refs., 7 figs., 5 tabs.

  17. Experimental (X-ray, (13)C CP/MAS NMR, IR, RS, INS, THz) and Solid-State DFT Study on (1:1) Co-Crystal of Bromanilic Acid and 2,6-Dimethylpyrazine.

    PubMed

    Łuczyńska, Katarzyna; Drużbicki, Kacper; Lyczko, Krzysztof; Dobrowolski, Jan Cz

    2015-06-04

    A combined structural, vibrational spectroscopy, and solid-state DFT study of the hydrogen-bonded complex of bromanilic acid with 2,6-dimethylpyrazine is reported. The crystallographic structure was determined by means of low-temperature single-crystal X-ray diffraction, which reveals the molecular units in their native protonation states, forming one-dimensional infinite nets of moderate-strength O···H-N hydrogen bonds. The nature of the crystallographic forces, stabilizing the studied structure, has been drawn by employing the noncovalent interactions analysis. It was found that, in addition to the hydrogen bonding, the intermolecular forces are dominated by stacking interactions and C-H···O contacts. The thermal and calorimetric analysis was employed to probe stability of the crystal phase. The structural analysis was further supported by a computationally assisted (13)C CP/MAS NMR study, providing a complete assignment of the recorded resonances. The vibrational dynamics was explored by combining the optical (IR, Raman, TDs-THz) and inelastic neutron scattering (INS) spectroscopy techniques with the state-of-the-art solid-state density functional theory (DFT) computations. Despite the quasi-harmonic approximation assumed throughout the study, an excellent agreement between the theoretical and experimental data was achieved over the entire spectral range, allowing for a deep and possibly thorough understanding of the vibrational characteristics of the system. Particularly, the significant influence of the long-range dipole coupling on the IR spectrum has been revealed. On the basis of a wealth of information gathered, the recent implementation of a dispersion-corrected linear-response scheme has been extensively examined.

  18. Lead hydro sodalite [Pb2(OH)(H2O)3]2[Al3Si3O12]2: synthesis and structure determination by combining X-ray rietveld refinement, 1H MAS NMR FTIR and XANES spectroscopy.

    PubMed

    Eiden-Assmann, S; Schneider, A M; Behrens, P; Wiebcke, M; Engelhardt, G; Felsche, J

    2000-01-01

    Ion exchange of the sodium hydro sodalites [Na3(H2O)4]2-[Al3Si3O12]2 [Na4(H3O2)]2[Al3Si3O12]2 and [Na4(OH)]2[Al3Si3O12]2 with aqueous Pb(NO3)2 solutions yielded, whichever reactant sodalite phase was used, the same lead hydro sodalite, [Pb2(OH)-(H2O)3]2[Al3Si3O12]2. Thus, in the case of the non-basic reactant [Na3(H2O)4]2-[Al3Si3O12]2 an overexchange occurs with respect to the number of nonframework cationic charges. Rietveld structure refinement of the lead hydro sodalite based on powder X-ray diffraction data (cubic, a = 9.070 A, room temperature, space group P43n) revealed that the two lead cations within each polyhedral sodalite cage form an orientationally disordered dinuclear [Pb2(micro-OH)(micro-H2O)(H2O)2]3+ complex. Due to additional lead framework oxygen bonds the coordination environment of each metal cation (CN 3+3) is approximately spherical, and clearly the lead 6s electron lone pair is stereochemically inactive. This is also suggested by the absence of a small peak at 13.025 keV, attributed in other Pb2+-O compounds to an electronic 2p-6s transition, in the PbL3 edge XANES spectrum. 1H MAS NMR and FTIR spectra show that the hydrogen atoms of the aqua hydroxo complex (which could not be determined in the Rietveld analysis) are involved in hydrogen bonds of various strengths.

  19. Study of the 11 B(p,p‧ γ) 11 B reaction for PIGE applications

    NASA Astrophysics Data System (ADS)

    Preketes-Sigalas, K.; Lagoyannis, A.; Axiotis, M.; Harissopulos, S.; Kokkoris, M.; Mertzimekis, T. J.; Paneta, V.; Provatas, G.

    2016-02-01

    The differential cross sections of the 2125 keV γ -ray, emitted by the 11 B(p,p‧ γ) 11 B reaction were measured at six (6) angles and at proton energies from 2.5 to 5.0 MeV. The experimental setup consisted of three (3) 100% relative efficiency HPGe detectors placed on a motorized turntable. The comparison between the present measurements, which have an overall uncertainty of ∼ 8%, and previous ones from literature gives contradictory results. While there are large differences with previous differential cross-section measurements from literature, there is good agreement with previous thick-target yield ones. Additional thick-target measurements were performed in an effort to explain the observed discrepancies.

  20. 1H and 13C MAS NMR analysis for the role of chemically inequivalent a-N(CH3)4 and b-N(CH3)4 ions in [N(CH3)4]2CuCl4

    NASA Astrophysics Data System (ADS)

    Lim, Ae Ran

    2014-01-01

    The spin-lattice relaxation times in the laboratory frame, T1, and in the rotating frame, T1ρ, for 1H and 13C in [N(CH3)4]2CuCl4 were measured by static NMR and magic angle spinning (MAS) NMR as functions of temperature. The intensities of the 1H and 13C signals changed near phase transition temperatures TC1 and TC3, which indicated that N(CH3)4 plays an important role in these phase transitions. It was thus apparent that the T1 and T1ρ for 1H are governed by the same molecular motions. Two inequivalent ions, a-N(CH3)4 and b-N(CH3)4, were identified by 13C cross-polarization (CP)/MAS NMR. From these results, the behaviors of these two chemically inequivalent N(CH3)4 groups in the paraelastic and ferroelastic phases are discussed.

  1. 27Al, 47,49Ti, 31P, and 13C MAS NMR Study of VX, GD, and HD Reactions with Nanosize Al2O3, Conventional Al2O3 and TiO2, and Aluminum and Titanium Metal

    DTIC Science & Technology

    2007-01-01

    reactions involved and peak assignments for titanophosphonate 3, Ti(m) and anatase (see text). 17568 J. Phys. Chem. C , Vol. 111, No. 47, 2007 Wagner et al...postulated to be Ti(O)[O2P(CH3)OPin]2, in agreement with elemental analysis. High-field 47,49Ti MAS NMR of anatase shows marked narrowing of its signals...Metal 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: Reactions of VX, GD, and HD with Al2O3, TiO2 ( anatase and rutile), aluminum, and titanium metal

  2. Heavy ion collision dynamics of 10,11B+10,11B reactions

    NASA Astrophysics Data System (ADS)

    Singh, BirBikram; Kaur, Manpreet; Kaur, Varinderjit; Gupta, Raj K.

    2015-01-01

    The dynamical cluster-decay model (DCM) of Gupta and collaborators has been applied successfully to the decay of very-light (A ˜ 30), light (A ˜ 40-80), medium, heavy and super-heavy mass compound nuclei for their decay to light particles (evaporation residues, ER), fusion-fission (ff), and quasi-fission (qf) depending on the reaction conditions. We intend to extend here the application of DCM to study the extreme case of decay of very-light nuclear systems 20,21,22Ne∗ formed in 10,11B+10,11B reactions, for which experimental data is available for their binary symmetric decay (BSD) cross sections, i.e., σBSD. For the systems under study, the calculations are presented for the σBSD in terms of their preformation and barrier penetration probabilities P0 and P. Interesting results are that in the decay of such lighter systems there is a competing reaction mechanism (specifically, the deep inelastic orbiting of non-compound nucleus (nCN) origin) together with ff. We have emipirically estimated the contribution of σnCN. Moreover, the important role of nuclear structure characteristics via P0 as well as angular momentum ℓ in the reaction dynamics are explored in the study.

  3. ATP11B Mediates Platinum Resistance in Ovarian Cancer

    DTIC Science & Technology

    2013-05-01

    A2780-CP20 cells (Supplemental Figure 7). To exam- ine the subcellular localization of ATP11B by immunofluorescence staining, we used specific cell...presence of 2 μM cisplatin, ATP11B was found in the nuclei of a limited number of cells. To further analyze the subcellular local - ization of ATP11B in the...TGN (27, 28). Our pharmacological studies demonstrated that both of these Figure 5 Subcellular localization of ATP11B in cisplatin-sensitive and

  4. Structure in solid state of 3,3‧-diindolylmethane derivatives, potent cytotoxic agents against human tumor cells, followed X-ray diffraction and 13C CP/MAS NMR analyses

    NASA Astrophysics Data System (ADS)

    Maciejewska, Dorota; Wolska, Irena; Niemyjska, Maria; Żero, Paweł

    2005-10-01

    The 5,5'-disubstituted-3,3'-diindolylmethanes 1, 2 have been prepared and their structure was analyzed by X-ray and NMR techniques. The X-ray diffraction studies revealed interesting C-H⋯ π intermolecular interactions which may play role in characterization of their biological features. In 1H and 13C NMR spectra in solution and in 13C CPMAS NMR spectra in solid state only a single pattern of signals was observed. Both compounds reduce the growth of MCF7 (breast), NCI-H460 (lung), and SF-268 (NCS) cells dramatically.

  5. Probing the nanostructure, interfacial interaction, and dynamics of chitosan-based nanoparticles by multiscale solid-state NMR.

    PubMed

    Wang, Fenfen; Zhang, Rongchun; Wu, Qiang; Chen, Tiehong; Sun, Pingchuan; Shi, An-Chang

    2014-12-10

    Chitosan-based nanoparticles (NPs) are widely used in drug and gene delivery, therapy, and medical imaging, but a molecular-level understanding of the internal morphology and nanostructure size, interface, and dynamics, which is critical for building fundamental knowledge for the precise design and efficient biological application of the NPs, remains a great challenge. Therefore, the availability of a multiscale (0.1-100 nm) and nondestructive analytical technique for examining such NPs is of great importance for nanotechnology. Herein, we present a new multiscale solid-state NMR approach to achieve this goal for the investigation of chitosan-poly(N-3-acrylamidophenylboronic acid) NPs. First, a recently developed (13)C multiple cross-polarization magic-angle spinning (MAS) method enabled fast quantitative determination of the NPs' composition and detection of conformational changes in chitosan. Then, using an improved (1)H spin-diffusion method with (13)C detection and theoretical simulations, the internal morphology and nanostructure size were quantitatively determined. The interfacial coordinated interaction between chitosan and phenylboronic acid was revealed by one-dimensional MAS and two-dimensional (2D) triple-quantum MAS (11)B NMR. Finally, dynamic-editing (13)C MAS and 2D (13)C-(1)H wide-line separation experiments provided details regarding the componential dynamics of the NPs in the solid and swollen states. On the basis of these NMR results, a model of the unique nanostructure, interfacial interaction, and componential dynamics of the NPs was proposed.

  6. Structural investigation of BaOsbnd B2O3sbnd P2O5 glasses by NMR and Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Koudelka, Ladislav; Kalenda, Petr; Mošner, Petr; Černošek, Zdeněk; Montagne, Lionel; Revel, Bertrand

    2016-09-01

    Glasses of the ternary system BaOsbnd B2O3sbnd P2O5 were prepared and studied in broad concentration limits covering the whole vitrification domain: 20-50 mol% BaO, 0-40 mol% B2O3 and 20-60 mol% P2O5. Their structure was studied with combinations of Raman spectroscopy, 31P MAS NMR spectroscopy and 11B MAS NMR spectroscopy. The obtained results are discussed in several compositional lines A: (100-x)Ba(PO3)2sbnd xB2O3, B: 40BaOsbnd yB2O3sbnd (60-y)P2O5, C: (50-z)BaOsbnd zB2O3sbnd 50P2O5, D: (60-w)BaOsbnd wB2O3sbnd 40P2O5 and E: uBaOsbnd 40B2O3sbnd (60-u)P2O5. Boron oxide incorporates into the phosphate network in the form of BO4 and BO3 groups and increases their glass transition temperature. Nevertheless, the increase in Tg is only steep within the region of 0-20 mol% B2O3 reaching a maximum at the glasses with ∼30 mol% B2O3. In the lines A, B and E a decrease in the P2O5 and an increase of B2O3 content results in the shortening of phosphate chains with decreasing P2O5 content; these changes are most pronounced in line B with a constant BaO content. In lines C and D with a constant P2O5 content a decrease in the BaO content results, in contrast, in the reverse transformation of phosphate structural units in the direction Q1 → Q2 → Q3 as detected from Raman spectra and 31P MAS NMR spectra. 11B MAS NMR spectra revealed that only BO4 units are present in the glasses with 0-20 mol% B2O3. In the glasses of the E series the fraction of BO3 units increases with a decreasing P2O5 content. By the decomposition of the 11B MAS NMR spectra it is possible to estimate the fractions of basic structural units formed by boron - B(OP)3O, B(OP)2O2 and BO3 in all the glasses of the glass forming region.

  7. A record of Neogene seawater δ11B reconstructed from paired δ11B analyses on benthic and planktic foraminifera

    NASA Astrophysics Data System (ADS)

    Greenop, Rosanna; Hain, Mathis P.; Sosdian, Sindia M.; Oliver, Kevin I. C.; Goodwin, Philip; Chalk, Thomas B.; Lear, Caroline H.; Wilson, Paul A.; Foster, Gavin L.

    2017-02-01

    The boron isotope composition (δ11B) of foraminiferal calcite reflects the pH and the boron isotope composition of the seawater the foraminifer grew in. For pH reconstructions, the δ11B of seawater must therefore be known, but information on this parameter is limited. Here we reconstruct Neogene seawater δ11B based on the δ11B difference between paired measurements of planktic and benthic foraminifera and an estimate of the coeval water column pH gradient from their δ13C values. Carbon cycle model simulations underscore that the ΔpH-Δδ13C relationship is relatively insensitive to ocean and carbon cycle changes, validating our approach. Our reconstructions suggest that δ11Bsw was ˜ 37.5 ‰ during the early and middle Miocene (roughly 23-12 Ma) and rapidly increased during the late Miocene (between 12 and 5 Ma) towards the modern value of 39.61 ‰. Strikingly, this pattern is similar to the evolution of the seawater isotope composition of Mg, Li and Ca, suggesting a common forcing mechanism. Based on the observed direction of change, we hypothesize that an increase in secondary mineral formation during continental weathering affected the isotope composition of riverine input to the ocean since 14 Ma.

  8. Breadboard RL10-11B low thrust operating mode

    NASA Technical Reports Server (NTRS)

    Kmiec, Thomas D.; Galler, Donald E.

    1987-01-01

    Cryogenic space engines require a cooling process to condition engine hardware to operating temperature before start. This can be accomplished most efficiently by burning propellants that would otherwise be dumped overboard after cooling the engine. The resultant low thrust operating modes are called Tank Head Idle and Pumped Idle. During February 1984, Pratt & Whitney conducted a series of tests demonstrating operation of the RL10 rocket engines at low thrust levels using a previously untried hydrogen/oxygen heat exchanger. The initial testing of the RL10-11B Breadboard Low Thrust Engine is described. The testing demonstrated operation at both tank head idle and pumped idle modes.

  9. Common polymorphisms in the CYP11B1 and CYP11B2 genes: evidence for a digenic influence on hypertension.

    PubMed

    Alvarez-Madrazo, Samantha; Mackenzie, Scott M; Davies, Eleanor; Fraser, Robert; Lee, Wai-Kwong; Brown, Morris; Caulfield, Mark J; Dominiczak, Anna F; Farrall, Martin; Lathrop, Mark; Hedner, Thomas; Melander, Olle; Munroe, Patricia B; Samani, Nilesh; Stewart, Paul M; Wahlstrand, Björn; Webster, John; Palmer, Colin N A; Padmanabhan, Sandosh; Connell, John M

    2013-01-01

    The locus encompassing the corticosteroidogenic genes CYP11B2 and CYP11B1 is of potential importance in essential hypertension. We analyzed the association of polymorphisms at this locus with risk of essential hypertension, using 2 white case-control collections for discovery (n=3340) and confirmation (n=2929). Single-marker and haplotype analyses were performed, with the CYP11B2 Intron 2 Conversion polymorphism showing strongest association with hypertension in both cohorts and in combined analysis (odds ratio=1.16, P=8.54×10(-5)). The CYP11B1 ACA haplotype associated with increased risk of hypertension relative to the alternative, GTC (odds ratio=1.11; P=7.4×10(-3)), whereas the CYP11B2 TWtC haplotype seemed protective relative to the contrasting CConvT (odds ratio=0.88, P=2.2×10(-3)). Analysis spanning the whole CYP11B1/CYP11B2 locus showed that haplotypes associated with raised risk of hypertension tend to coexist. Functional analysis of heterozygous human adrenal tissue demonstrated decreased CYP11B2 expression and increased CYP11B1 expression for those alleles associating with reduced risk of hypertension. These results confirm the hypertensive influence of this locus, with data suggesting a complex digenic mechanism whereby altered relative CYP11B1 and CYP11B2 gene expression could have a chronic effect on enzyme activity and corticosteroid synthesis.

  10. Exoplanet HAT-P-11b Secondary Transit Observations

    NASA Technical Reports Server (NTRS)

    Barry, Richard K., Jr.

    2010-01-01

    We have conducted secondary eclipse observations of exoplanet HAT--11b, recently discovered by proposal G. Bakos and his colleagues. HAT-P-11b is the smallest transiting extrasolar planet yet found and one of only two known exo-Neptunes. We have observed the system at 3.6 microns for a period of 22 hours centered on the anticipated secondary eclipse time, to detect the eclipse and determine its phase. Once the secondary eclipse is located through analysis of the data, we will make a more focused series of observations in both the 3.6 and 4.5 micron bands to fully characterize it. HAT-P-1lb has a period of 4.8878 days, radius of 0.422 RJ, mass of 0.081 MJ and semi major axis 0.053 AU. Measurements of the secondary eclipse will clarify two key issues; 1) the planetary brightness temperature and the nature of its atmosphere, and 2) the eccentricity of its orbit, with implications for its dynamical evolution. A precise determination of the orbit phase for the secondary eclipse will also be of great utility for Kepler observations of this system at visible wavelengths.

  11. Development of CYP11B1 and CYP11B2 assays utilizing homogenates of adrenal glands: Utility of monkey as a surrogate for human.

    PubMed

    Cerny, Matthew A; Csengery, Alexander; Schmenk, Jennifer; Frederick, Kosea

    2015-11-01

    Elevated levels of aldosterone are associated with arterial hypertension, congestive heart failure, chronic kidney disease, and obesity. Aldosterone is produced predominantly in the zona glomerulosa of the cortex of the adrenal gland by the enzyme aldosterone synthase (CYP11B2). Treatment of the above indications by decreasing production of aldosterone is thought to be of therapeutic benefit by lessening the deleterious effects of aldosterone mediated through both the mineralocorticoid receptor and also through so called non-genomic pathways. However, inhibition of the highly similar enzyme, CYP11B1, which is responsible for the production of cortisol, must be avoided in the development of clinically useful aldosterone synthase inhibitors due to the resulting impairment of the cortisol-induced stress response. In efforts to assess the interactions of compounds with the CYP11B enzymes, a variety of cell-based inhibitor screening assays for both CYP11B1 and CYP11B2 have been reported. Herein we report details of assays employing both cynomolgus monkey adrenal homogenate (CAH) and human adrenal homogenate (HAH) as sources of CYP11B1 and CYP11B2 enzymes. Utilizing both CAH and HAH, we have characterized the kinetics of the CYP11B1-mediated conversion of 11-deoxycortisol to cortisol and the CYP11B2-mediated oxidation of corticosterone to aldosterone. Inhibition assays for both CYP11B1 and CYP11B2 were subsequently developed. Based on a comparison of human and monkey amino acid sequences, kinetics data, and inhibition values derived from the HAH and CAH assays, evidence is provided in support of using cynomolgus monkey tissue-derived cell homogenates as suitable surrogates for the human enzymes.

  12. Association of BAP31 with CD11b/CD18. Potential role in intracellular trafficking of CD11b/CD18 in neutrophils.

    PubMed

    Zen, Ke; Utech, Markus; Liu, Yuan; Soto, Illena; Nusrat, Asma; Parkos, Charles A

    2004-10-22

    The beta2 integrin CD11b/CD18 is an integral membrane protein that is present in the plasma membrane and secondary granules of neutrophils and functions as a major adhesion molecule. Upon cellular activation, there is translocation of intracellular pools of CD11b/CD18 to the plasma membrane in concert with enhanced cellular adhesion. Although much is known about the function of CD11b/CD18, how this protein is transported within the cell is less well defined. Here we report that CD11b/CD18 specifically binds to BAP31, a member of a novel class of sorting proteins regulating cellular anterograde transport. Through experiments aimed at identifying CD11b/CD18-binding proteins, we produced a monoclonal antibody termed E1B2 that recognizes a 28-kDa membrane protein that co-precipitates with CD11b/CD18. Microsequence analysis of the E1B2 antigen revealed that it is BAP31. Co-association of CD11b/CD18 and BAP31 was confirmed in co-immunoprecipitation and protein binding assays. Additional experiments revealed that the binding of BAP31 to CD11b/CD18 was not dependent on divalent cations nor mediated by the I-domain of CD11b. Using glutathione S-transferase fusion chimeras, we determined that binding of CD11b/CD18 to BAP31 is mediated through interactions with the cytoplasmic tail of BAP31. Immunolocalization studies revealed colocalization of BAP31 and CD11b/CD18 within neutrophil secondary granules. Subcellular fractionation studies in polymorphonuclear leukocytes (PMN) revealed similar patterns of redistribution of BAP31 and CD11b/CD18 from fractions enriched in secondary granules to the plasma membrane following stimulation with formylmethionylleucylphenylalanine (fMLP). Given the known sorting properties of BAP31, these findings suggest that BAP31 may play a role in regulating intracellular trafficking of CD11b/CD18 in neutrophils.

  13. Flavonoids exhibit diverse effects on CYP11B1 expression and cortisol synthesis

    SciTech Connect

    Cheng, Li-Chuan; Li, Lih-Ann

    2012-02-01

    CYP11B1 catalyzes the final step of cortisol biosynthesis. The effects of flavonoids on transcriptional expression and enzyme activity of CYP11B1 were investigated using the human adrenocortical H295R cell model. All tested nonhydroxylated flavones including 3′,4′-dimethoxyflavone, α-naphthoflavone, and β-naphthoflavone upregulated CYP11B1 expression and cortisol production, whereas apigenin and quercetin exhibited potent cytotoxicity and CYP11B1 repression at high concentrations. Nonhydroxylated flavones stimulated CYP11B1-catalyzed cortisol formation at transcriptional level. Resveratrol increased endogenous and substrate-supported cortisol production like nonhydroxylated flavones tested, but it had no effect on CYP11B1 gene expression and enzyme activity. Resveratrol appeared to alter cortisol biosynthesis at an earlier step. The Ad5 element situated in the − 121/− 106 region was required for basal and flavone-induced CYP11B1 expression. Overexpression of COUP-TFI did not improve the responsiveness of Ad5 to nonhydroxylated flavones. Although COUP-TFI overexpression increased CYP11B1 and CYP11B2 promoter activation, its effect was not mediated through the common Ad5 element. Treating cells with PD98059 (a flavone-type MEK1 inhibitor) increased CYP11B1 promoter activity, but not involving ERK signaling because phosphorylation of ERK1/2 remained unvarying throughout the course of treatment. Likewise, AhR was not responsible for the CYP11B1-modulating effects of flavonoids because inconsistency with their effects on AhR activation. 3′,4′-dimethoxyflavone and 8-Br-cAMP additively activated CYP11B1 promoter activity. H-89 reduced 3′,4′-dimethoxyflavone-induced CYP11B1 promoter activation but to a lesser extent as compared to its inhibition on cAMP-induced transactivation. Our data suggest that constant exposure to nonhydroxylated flavones raises a potential risk of high basal and cAMP-induced cortisol synthesis in consequence of increased CYP11B1

  14. A (25)Mg, (89)Y and (115)In solid state MAS NMR study of YT2X and Y(T0.5T'0.5)2X (T/T' = Pd, Ag, Au; X = Mg, In) Heusler phases.

    PubMed

    Benndorf, Christopher; Stein, Sebastian; Heletta, Lukas; Kersting, Marcel; Eckert, Hellmut; Pöttgen, Rainer

    2016-12-20

    Yttrium-transition metal-magnesium (indium) Heusler phases YPd2Mg, YPd2In, YAg2Mg, YAg2In, YAu2Mg, and YAu2In and their quaternary compounds (solid solutions) Y(Pd0.5Ag0.5)2Mg, Y(Pd0.5Ag0.5)2In, Y(Pd0.5Au0.5)2Mg, Y(Pd0.5Au0.5)2In, Y(Ag0.5Au0.5)2Mg and Y(Ag0.5Au0.5)2In were synthesized from the elements in sealed niobium ampoules in a high-frequency furnace or by arc-melting, respectively. All compounds crystallize with the cubic MnCu2Al type structure (Heusler phase), space group Fm3[combining macron]m. The structure of Y(Ag0.39Au0.61)2Mg was refined from single crystal X-ray diffractometer data: a = 689.97(5) pm, wR2 = 0.0619, 52 F(2) values, 6 parameters. Magnetic susceptibility measurements show Pauli paramagnetic behavior for all samples. The compounds were investigated by (25)Mg, (89)Y and (115)In solid state MAS NMR spectroscopy. Large positive resonance shifts are observed for all nuclei. A review of the present data in the context of literature data on isotypic Heusler phases with Cd and Sn indicates that the (89)Y shifts show a correlation with the electronegativity of the main group atoms (Mg, Cd, In, Sn). The solid solutions Y(Ag1-xTx)2Mg (x = 0.1, 0.25, 0.33, 0.5; T = Pd, Au) clearly show Vegard-like behavior concerning their lattice parameters, and their main group element resonance shifts arising from spin and orbital contributions are close to the interpolated values of the corresponding end-member compounds.

  15. Direct Observation of Lattice Aluminum Environments in Li Ion Cathodes LiNi 1–yz Co y Al z O 2 and Al-Doped LiNi x Mn y Co z O 2 via 27 Al MAS NMR Spectroscopy

    SciTech Connect

    Dogan, Fulya; Vaughey, John T.; Iddir, Hakim; Key, Baris

    2016-07-06

    Direct observations of local lattice aluminum environments have been a major challenge for aluminum -bearing Li ion battery materials, such as LiNi1-y-zCoyAlzO2 Al(NCA) and aluminum-doped LiNixMnyCozO2 (NMC). Al-27 magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy is the only structural probe currently available that can qualitatively and quantitatively characterize lattice and nonlattice (i.e., surface, coatings, segregation, secondary phase etc.) aluminum coordination and provide information that helps discern its effect in the lattice. In the present study, we use NMR to gain new insights into transition metal (TM)-O-Al coordination and evolution of lattice aluminum sites upon cycling. With the aid of first-principles DFT calculations, we show direct evidence of lattice Al sites, nonpreferential Ni/Co-O-Al ordering in NCA, and the lack of bulk lattice aluminum in aluminum -"doped" NMC. Aluminum coordination of the paramagnetic (lattice) and diamagnetic (nonlattice) nature is investigated for Al-doped NMC and NCA. For the latter, the evolution of the lattice site(s) upon cycling is also studied. A clear reordering of lattice aluminum environments due to nickel migration is observed in NCA upon extended cycling.

  16. Solid-state NMR Study of Ion Adsorption and Charge Storage in Graphene Film Supercapacitor Electrodes

    PubMed Central

    Li, Kecheng; Bo, Zheng; Yan, Jianhua; Cen, Kefa

    2016-01-01

    Graphene film has been demonstrated as promising active materials for electric double layer capacitors (EDLCs), mainly due to its excellent mechanical flexibility and freestanding morphology. In this work, the distribution and variation pattern of electrolyte ions in graphene-film based EDLC electrodes are investigated with a 11B magic-angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy. For neutral graphene films soaked with different amounts of electrolytes (1 M TEABF4/ACN), weakly and strongly adsorbed anions are identified based on the resonances at different 11B chemical shifts. Unlike other porous carbonaceous materials, the strongly adsorbed anions are found as the major electrolyte anions components in graphene films. Further measurements on the ion population upon charging are carried out with applying different charging voltages on the graphene films. Results indicate that the charging process of graphene-film based EDLCs can be divided into two distinct charge storage stages (i.e., ejection of co-ions and adsorption of counter-ions) for different voltages. The as-obtained results will be useful for the design and fabrication of high performance graphene-film based EDLCs. PMID:28000786

  17. Solid-state NMR Study of Ion Adsorption and Charge Storage in Graphene Film Supercapacitor Electrodes

    NASA Astrophysics Data System (ADS)

    Li, Kecheng; Bo, Zheng; Yan, Jianhua; Cen, Kefa

    2016-12-01

    Graphene film has been demonstrated as promising active materials for electric double layer capacitors (EDLCs), mainly due to its excellent mechanical flexibility and freestanding morphology. In this work, the distribution and variation pattern of electrolyte ions in graphene-film based EDLC electrodes are investigated with a 11B magic-angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy. For neutral graphene films soaked with different amounts of electrolytes (1 M TEABF4/ACN), weakly and strongly adsorbed anions are identified based on the resonances at different 11B chemical shifts. Unlike other porous carbonaceous materials, the strongly adsorbed anions are found as the major electrolyte anions components in graphene films. Further measurements on the ion population upon charging are carried out with applying different charging voltages on the graphene films. Results indicate that the charging process of graphene-film based EDLCs can be divided into two distinct charge storage stages (i.e., ejection of co-ions and adsorption of counter-ions) for different voltages. The as-obtained results will be useful for the design and fabrication of high performance graphene-film based EDLCs.

  18. Solid-state NMR Study of Ion Adsorption and Charge Storage in Graphene Film Supercapacitor Electrodes.

    PubMed

    Li, Kecheng; Bo, Zheng; Yan, Jianhua; Cen, Kefa

    2016-12-21

    Graphene film has been demonstrated as promising active materials for electric double layer capacitors (EDLCs), mainly due to its excellent mechanical flexibility and freestanding morphology. In this work, the distribution and variation pattern of electrolyte ions in graphene-film based EDLC electrodes are investigated with a (11)B magic-angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy. For neutral graphene films soaked with different amounts of electrolytes (1 M TEABF4/ACN), weakly and strongly adsorbed anions are identified based on the resonances at different (11)B chemical shifts. Unlike other porous carbonaceous materials, the strongly adsorbed anions are found as the major electrolyte anions components in graphene films. Further measurements on the ion population upon charging are carried out with applying different charging voltages on the graphene films. Results indicate that the charging process of graphene-film based EDLCs can be divided into two distinct charge storage stages (i.e., ejection of co-ions and adsorption of counter-ions) for different voltages. The as-obtained results will be useful for the design and fabrication of high performance graphene-film based EDLCs.

  19. Study of rlastic and inelastic {sup 11}B +α scattering and search for cluster states of enlarged radius in {sup 11}B

    SciTech Connect

    Danilov, A. N. Demyanova, A. S.; Dmitriev, S. V.; Ogloblin, A. A.; Belyaeva, T. L.; Goncharov, S. A.; Gurov, Yu. B.; Maslov, V. A.; Sobolev, Yu. G.; Trzaska, W.; Khlebnikov, S. V.; Heikkinen, P.; Julin, R.; Tyurin, G. P.; Burtebaev, N.; Zholdybayev, T.

    2015-09-15

    The differential cross sections for elastic and inelastic {sup 11}B + α scattering were measured at the alpha-particle energy of 65 MeV, the inelastic-scattering processes leading to the excitation of known states of {sup 11}B up to excitation energies of about 14 MeV. Data on elastic scattering were analyzed together with those that were published earlier for lower energies. The cross sections for inelastic scattering were analyzed on the basis of the distorted-wave method. A modified diffractionmodel was used to determine the root-mean-square radii of excited states. The radii of states whose excitation energies were below about 7MeV were found to agree with radius of the ground state to within 0.1 to 0.15 fm. This result complieswith the traditional idea that the low-lying states of {sup 11}B have a shell structure. The possibility that these states belong to the predicted rotational bands, which, if any, are truncated to three states, cannot be ruled out either. The majority of the observed highly excited states are distributed among four rotational bands. The moments of inertia of these bands are close; for the band based on the 3/2{sup −} state at E* = 8.56 MeV, they are even higher than those of the Hoyle state in the {sup 12}C nucleus. The measured radii of states associated with these bands of {sup 11}B are larger than the ground-state radius by 0.7 to 1.0 fm and are also close to the radius of the Hoyle state. The results of the present study agree with the existing predictions that the cluster structure of the {sup 11}B nucleus is diverse at high excitation energies. The hypothesis that the {sup 11}B nucleus features a “giant” state of size commensurate with those in heavy nuclei was not confirmed.

  20. Two dimensional NMR and NMR relaxation studies of coal structure

    SciTech Connect

    Zilm, K.W.

    1989-01-01

    This report covers the progress made on the title project during the past reporting period. Four major areas of inquiry are being pursued. Advanced solid state NMR methods are being developed to assay the distribution of the various important functional groups in coals that determine the reactivity of coals. Other methods are being developed which will also determine how these functional groups are linked together. A third area of investigation concerns how molecular mobility in coals impacts NMR relaxation times, which is important for interpretation of such data in terms of the mobile phase in coals model. Along the same lines the authors are also using these studies to establish protocols for obtaining the best quantitative response from coals in solid state C-13 NMR spectra. The effects of very high MAS rates (>10 kHz) on cross polarization dynamics are also being investigated for similar reasons. The authors have been reinvestigating the prospects of using zero field NMR types of techniques for two dimensional NMR structural analysis of complex organic solids such as coals. Currently MAS spin rates are not sufficiently high to permit zero field in high field NMR for protons in typical organic solids, however they are compatible with {sup 13}C-{sup 13}C dipolar couplings. In collaboration with Dr. Robert Tycko of AT T Bell Laboratories, inventor of the zero field in high field NMR method, the authors have performed the first zero field in high field {sup 13}C NMR experiments. These results are described. 9 refs., 2 figs.

  1. CD11b is protective in complement-mediated immune complex glomerulonephritis.

    PubMed

    Alexander, Jessy J; Chaves, Lee D; Chang, Anthony; Jacob, Alexander; Ritchie, Maria; Quigg, Richard J

    2015-05-01

    In chronic serum sickness, glomerular immune complexes form, yet C57BL/6 mice do not develop glomerulonephritis unless complement factor H (CfH) is absent, indicating the relevance of complement regulation. Complement receptor 3 (CD11b) and Fcγ receptors on leukocytes, and CfH on platelets, can bind immune complexes. Here we induced immune complex-mediated glomerulonephritis in CfH(-/-) mice chimeric for wild-type, CfH(-/-), CD11b(-/-), or FcRγ(-/-) bone marrow stem cells. Glomerulonephritis was worse in CD11b(-/-) chimeras compared with all others, whereas disease in FcRγ(-/-) and wild-type chimeras was comparable. Disease tracked strongly with humoral immune responses, but not glomerular immune complex deposits. Interstitial inflammation with M1 macrophages strongly correlated with glomerulonephritis scores. CD11b(-/-) chimeras had significantly more M1 macrophages and CD4(+) T cells. The renal dendritic cell populations originating from bone marrow-derived CD11c(+) cells were similar in all experimental groups. CD11b(+) cells bearing colony-stimulating factor 1 receptor were present in kidneys, including CD11b(-/-) chimeras; these cells correlated negatively with glomerulonephritis scores. Thus, experimental immune complex-mediated glomerulonephritis is associated with accumulation of M1 macrophages and CD4(+) T cells in kidneys and functional renal insufficiency. Hence, CD11b on mononuclear cells is instrumental in generating an anti-inflammatory response in the inflamed kidney.

  2. Extracellular Release of CD11b by TLR9 Stimulation in Macrophages.

    PubMed

    Kim, Dongbum; Kim, Te Ha; Wu, Guang; Park, Byoung Kwon; Ha, Ji-Hee; Kim, Yong-Sung; Lee, Keunwook; Lee, Younghee; Kwon, Hyung-Joo

    2016-01-01

    CpG-DNA upregulates the expression of pro-inflammatory cytokines, chemokines and cell surface markers. Investigators have shown that CD11b (integrin αM) regulates TLR-triggered inflammatory responses in the macrophages and dendritic cells. Therefore, we aimed to identify the effects of CpG-DNA on the expression of CD11b in macrophages. There was no significant change in surface expression of CD11b after CpG-DNA stimulation. However, CD11b was released into culture supernatants after stimulation with phosphorothioate-backbone modified CpG-DNA such as PS-ODN CpG-DNA 1826(S). In contrast, MB-ODN 4531 and non-CpG-DNA control (regardless of backbone type and liposome-encapsulation) failed to induce release of CD11b. Therefore, the context of the CpG-DNA sequence and phosphorothioate backbone modification may regulate the effects of CpG-DNA on CD11b release. Based on inhibitor studies, CD11b release is mediated by p38 MAP kinase activation, but not by the PI3K and NF-κB activation. CD11b release is mediated by lysosomal degradation and by vacuolar acidification in response to CpG-DNA stimulation. The amount of CD11b in the exosome precipitant was significantly increased by CpG-DNA stimulation in vivo and in vitro depending on TLR9. Our observations perhaps give more insight into understanding of the mechanisms involved in CpG-DNA-induced immunomodulation in the innate immunity.

  3. Asynchronous combinatorial action of four regulatory factors activates Bcl11b for T cell commitment

    PubMed Central

    Kueh, Hao Yuan; Yui, Mary A.; Ng, Kenneth K.H.; Pease, Shirley S.; Zhang, Jingli A.; Damle, Sagar S.; Freedman, George; Siu, Sharmayne; Bernstein, Irwin D.; Elowitz, Michael B.; Rothenberg, Ellen V.

    2016-01-01

    During T cell development, multipotent progenitors relinquish competence for other fates and commit to the T cell lineage by turning on the transcription factor Bcl11b. To clarify lineage commitment mechanisms, we followed developing T cells at single-cell level using Bcl11b knock-in fluorescent reporter mice. Notch signaling and Notch-activated transcription factors collaborate to activate Bcl11b expression, irrespective of Notch-dependent proliferation. These inputs work via three distinct, asynchronous mechanisms: an early locus poising function dependent on TCF-1 and GATA-3; a stochastic permissivity function dependent on Notch signaling; and a separate amplitude-control function dependent on Runx1, a factor already present in multipotent progenitors. Despite all being necessary for Bcl11b activation, these inputs act in a stage specific manner, providing a multi-tiered mechanism for developmental gene regulation. PMID:27376470

  4. Human-specific gene ARHGAP11B promotes basal progenitor amplification and neocortex expansion.

    PubMed

    Florio, Marta; Albert, Mareike; Taverna, Elena; Namba, Takashi; Brandl, Holger; Lewitus, Eric; Haffner, Christiane; Sykes, Alex; Wong, Fong Kuan; Peters, Jula; Guhr, Elaine; Klemroth, Sylvia; Prüfer, Kay; Kelso, Janet; Naumann, Ronald; Nüsslein, Ina; Dahl, Andreas; Lachmann, Robert; Pääbo, Svante; Huttner, Wieland B

    2015-03-27

    Evolutionary expansion of the human neocortex reflects increased amplification of basal progenitors in the subventricular zone, producing more neurons during fetal corticogenesis. In this work, we analyze the transcriptomes of distinct progenitor subpopulations isolated by a cell polarity-based approach from developing mouse and human neocortex. We identify 56 genes preferentially expressed in human apical and basal radial glia that lack mouse orthologs. Among these, ARHGAP11B has the highest degree of radial glia-specific expression. ARHGAP11B arose from partial duplication of ARHGAP11A (which encodes a Rho guanosine triphosphatase-activating protein) on the human lineage after separation from the chimpanzee lineage. Expression of ARHGAP11B in embryonic mouse neocortex promotes basal progenitor generation and self-renewal and can increase cortical plate area and induce gyrification. Hence, ARHGAP11B may have contributed to evolutionary expansion of human neocortex.

  5. Two dimensional NMR and NMR relaxation studies of coal structure

    SciTech Connect

    Zilm, K.W.

    1989-01-01

    This report covers the progress made on the title project and summarizes the accomplishments for the project period. Four major areas of inquiry have been pursued. Advanced solid state NMR methods are being developed to assay the distribution of the various important functional groups in coals that determine the reactivity of coals. Other methods are being developed which will also determine how these functional groups are linked together. A third area of investigation concern how molecular mobility in coals impacts NMR relaxation times, which is important for interpretation of such data in terms of the mobile phase in coals model. Along the same lines we are also using these studies to establish protocols for obtaining the best quantitative response from coals in solid state C-13 NMR spectra. The effects of very high MAS rates (>10 kHz) on cross polarization dynamics are also being investigated for similar reasons. During the last quarter the authors have concentrated on improvements in cross polarization (CP) sequences with a goal of making the CP process insensitive to experimental conditions such as the magic angle spinning (MAS) rate. In order to be able to use fields the order of 7.0 T or higher, CP efficiency must be maintained at MAS rates of over 10 kHz. The standard sequences have severe limitations at these rates which lead to intensity distortions in {sup 13}C CPMAS spectra. Thus in order to be able to take advantage of the increases in sensitivity and resolution that accompany high field operation, improvements in the NMR methods are required. The new sequences the authors are developing will be especially important for quantitative analysis of coal structure by {sup 13}C solid state NMR at high field strengths. 13 refs., 7 figs., 2 tabs.

  6. Fluid flow dynamics in MAS systems.

    PubMed

    Wilhelm, Dirk; Purea, Armin; Engelke, Frank

    2015-08-01

    The turbine system and the radial bearing of a high performance magic angle spinning (MAS) probe with 1.3mm-rotor diameter has been analyzed for spinning rates up to 67kHz. We focused mainly on the fluid flow properties of the MAS system. Therefore, computational fluid dynamics (CFD) simulations and fluid measurements of the turbine and the radial bearings have been performed. CFD simulation and measurement results of the 1.3mm-MAS rotor system show relatively low efficiency (about 25%) compared to standard turbo machines outside the realm of MAS. However, in particular, MAS turbines are mainly optimized for speed and stability instead of efficiency. We have compared MAS systems for rotor diameter of 1.3-7mm converted to dimensionless values with classical turbomachinery systems showing that the operation parameters (rotor diameter, inlet mass flow, spinning rate) are in the favorable range. This dimensionless analysis also supports radial turbines for low speed MAS probes and diagonal turbines for high speed MAS probes. Consequently, a change from Pelton type MAS turbines to diagonal turbines might be worth considering for high speed applications. CFD simulations of the radial bearings have been compared with basic theoretical values proposing considerably smaller frictional loss values. The discrepancies might be due to the simple linear flow profile employed for the theoretical model. Frictional losses generated inside the radial bearings result in undesired heat-up of the rotor. The rotor surface temperature distribution computed by CFD simulations show a large temperature gradient over the rotor.

  7. Fluid flow dynamics in MAS systems

    NASA Astrophysics Data System (ADS)

    Wilhelm, Dirk; Purea, Armin; Engelke, Frank

    2015-08-01

    The turbine system and the radial bearing of a high performance magic angle spinning (MAS) probe with 1.3 mm-rotor diameter has been analyzed for spinning rates up to 67 kHz. We focused mainly on the fluid flow properties of the MAS system. Therefore, computational fluid dynamics (CFD) simulations and fluid measurements of the turbine and the radial bearings have been performed. CFD simulation and measurement results of the 1.3 mm-MAS rotor system show relatively low efficiency (about 25%) compared to standard turbo machines outside the realm of MAS. However, in particular, MAS turbines are mainly optimized for speed and stability instead of efficiency. We have compared MAS systems for rotor diameter of 1.3-7 mm converted to dimensionless values with classical turbomachinery systems showing that the operation parameters (rotor diameter, inlet mass flow, spinning rate) are in the favorable range. This dimensionless analysis also supports radial turbines for low speed MAS probes and diagonal turbines for high speed MAS probes. Consequently, a change from Pelton type MAS turbines to diagonal turbines might be worth considering for high speed applications. CFD simulations of the radial bearings have been compared with basic theoretical values proposing considerably smaller frictional loss values. The discrepancies might be due to the simple linear flow profile employed for the theoretical model. Frictional losses generated inside the radial bearings result in undesired heat-up of the rotor. The rotor surface temperature distribution computed by CFD simulations show a large temperature gradient over the rotor.

  8. Radio Frequency Fingerprinting Techniques Through Preamble Modification in IEEE 802.11B

    DTIC Science & Technology

    2014-06-30

    David Bull, and Joseph McGeehan. “A Comparison of the HIPERLAN/2 and IEEE 802.11a Wireless LAN Standards”, Communications Magazine , IEEE , vol. 40, no...RADIO FREQUENCY FINGERPRINTING TECHNIQUES THROUGH PREAMBLE MODIFICATION IN IEEE 802.11B THESIS Nicholas J. Kulesza, Captain, USAF AFIT–ENG–T–14–J–8...MODIFICATION IN IEEE 802.11B THESIS Presented to the Faculty Department of Electrical and Computer Engineering Graduate School of Engineering and Management

  9. Migration of CD11b+ accessory cells during murine lung regeneration.

    PubMed

    Chamoto, Kenji; Gibney, Barry C; Lee, Grace S; Ackermann, Maximilian; Konerding, Moritz A; Tsuda, Akira; Mentzer, Steven J

    2013-05-01

    In many mammalian species, the removal of one lung leads to growth of the remaining lung to near-baseline levels. In studying post-pneumonectomy mice, we used morphometric measures to demonstrate neoalveolarization within 21 days of pneumonectomy. Of note, the detailed histology during this period demonstrated no significant pulmonary inflammation. To identify occult blood-borne cells, we used a parabiotic model (wild-type/GFP) of post-pneumonectomy lung growth. Flow cytometry of post-pneumonectomy lung digests demonstrated a rapid increase in the number of cells expressing the hematopoietic membrane molecule CD11b; 64.5% of the entire GFP(+) population were CD11b(+). Fluorescence microscopy demonstrated that the CD11b(+) peripheral blood cells migrated into both the interstitial tissue and alveolar airspace compartments. Pneumonectomy in mice deficient in CD11b (CD18(-/-) mutants) demonstrated near-absent leukocyte migration into the airspace compartment (p<.001) and impaired lung growth as demonstrated by lung weight (p<.05) and lung volume (p<.05). Transcriptional activity of the partitioned CD11b(+) cells demonstrated significantly increased transcription of Angpt1, Il1b, and Mmp8, Mmp9, Ncam1, Sele, Sell, Selp in the alveolar airspace and Adamts2, Ecm1, Egf, Mmp7, Npr1, Tgfb2 in the interstitial tissue (>4-fold regulation; p<.05). These data suggest that blood-borne CD11b(+) cells represent a population of accessory cells contributing to post-pneumonectomy lung growth.

  10. BCL11B expression in intramembranous osteogenesis during murine craniofacial suture development.

    PubMed

    Holmes, Greg; van Bakel, Harm; Zhou, Xueyan; Losic, Bojan; Jabs, Ethylin Wang

    2015-01-01

    Sutures, where neighboring craniofacial bones are separated by undifferentiated mesenchyme, are major growth sites during craniofacial development. Pathologic fusion of bones within sutures occurs in a wide variety of craniosynostosis conditions and can result in dysmorphic craniofacial growth and secondary neurologic deficits. Our knowledge of the genes involved in suture formation is poor. Here we describe the novel expression pattern of the BCL11B transcription factor protein during murine embryonic craniofacial bone formation. We examined BCL11B protein expression at E14.5, E16.5, and E18.5 in 14 major craniofacial sutures of C57BL/6J mice. We found BCL11B expression to be associated with all intramembranous craniofacial bones examined. The most striking aspects of BCL11B expression were its high levels in suture mesenchyme and increasingly complementary expression with RUNX2 in differentiating osteoblasts during development. BCL11B was also expressed in mesenchyme at the non-sutural edges of intramembranous bones. No expression was seen in osteoblasts involved in endochondral ossification of the cartilaginous cranial base. BCL11B is expressed to potentially regulate the transition of mesenchymal differentiation and suture formation within craniofacial intramembranous bone.

  11. BCL11B expression in intramembranous osteogenesis during murine craniofacial suture development

    PubMed Central

    Holmes, Greg; van Bakel, Harm; Zhou, Xueyan; Losic, Bojan; Jabs, Ethylin Wang

    2014-01-01

    Sutures, where neighboring craniofacial bones are separated by undifferentiated mesenchyme, are major growth sites during craniofacial development. Pathologic fusion of bones within sutures occurs in a wide variety of craniosynostosis conditions and can result in dysmorphic craniofacial growth and secondary neurologic deficits. Our knowledge of the genes involved in suture formation is poor. Here we describe the novel expression pattern of the BCL11B transcription factor protein during murine embryonic craniofacial bone formation. We examined BCL11B protein expression at E14.5, E16.5, and E18.5 in 14 major craniofacial sutures of C57BL/6J mice. We found BCL11B expression to be associated with all intramembranous craniofacial bones examined. The most striking aspects of BCL11B expression were its high levels in suture mesenchyme and increasingly complementary expression with RUNX2 in differentiating osteoblasts during development. BCL11B was also expressed in mesenchyme at the non-sutural edges of intramembranous bones. No expression was seen in osteoblasts involved in endochondral ossification of the cartilaginous cranial base. BCL11B is expressed to potentially regulate the transition of mesenchymal differentiation and suture formation within craniofacial intramembranous bone. PMID:25511173

  12. A single splice site mutation in human-specific ARHGAP11B causes basal progenitor amplification

    PubMed Central

    Florio, Marta; Namba, Takashi; Pääbo, Svante; Hiller, Michael; Huttner, Wieland B.

    2016-01-01

    The gene ARHGAP11B promotes basal progenitor amplification and is implicated in neocortex expansion. It arose on the human evolutionary lineage by partial duplication of ARHGAP11A, which encodes a Rho guanosine triphosphatase–activating protein (RhoGAP). However, a lack of 55 nucleotides in ARHGAP11B mRNA leads to loss of RhoGAP activity by GAP domain truncation and addition of a human-specific carboxy-terminal amino acid sequence. We show that these 55 nucleotides are deleted by mRNA splicing due to a single C→G substitution that creates a novel splice donor site. We reconstructed an ancestral ARHGAP11B complementary DNA without this substitution. Ancestral ARHGAP11B exhibits RhoGAP activity but has no ability to increase basal progenitors during neocortex development. Hence, a single nucleotide substitution underlies the specific properties of ARHGAP11B that likely contributed to the evolutionary expansion of the human neocortex. PMID:27957544

  13. CD11b(+) Mononuclear Cells Mitigate Hyperoxia-Induced Lung Injury in Neonatal Mice.

    PubMed

    Eldredge, Laurie C; Treuting, Piper M; Manicone, Anne M; Ziegler, Steven F; Parks, William C; McGuire, John K

    2016-02-01

    Bronchopulmonary dysplasia (BPD) is a common consequence of life-saving interventions for infants born with immature lungs. Resident tissue myeloid cells regulate lung pathology, but their role in BPD is poorly understood. To determine the role of lung interstitial myeloid cells in neonatal responses to lung injury, we exposed newborn mice to hyperoxia, a neonatal mouse lung injury model with features of human BPD. In newborn mice raised in normoxia, we identified a CD45(+) F4/80(+) CD11b(+), Ly6G(lo-int) CD71(+) population of cells in lungs of neonatal mice present in significantly greater percentages than in adult mice. In response to hyperoxia, surface marker and gene expression in whole lung macrophages/monocytes was biased to an alternatively activated phenotype. Partial depletion of these CD11b(+) mononuclear cells using CD11b-diphtheria toxin (DT) receptor transgenic mice resulted in 60% mortality by 40 hours of hyperoxia exposure with more severe lung injury, perivascular edema, and alveolar hemorrhage compared with DT-treated CD11b-DT receptor-negative controls, which displayed no mortality. These results identify an antiinflammatory population of CD11b(+) mononuclear cells that are protective in hyperoxia-induced neonatal lung injury in mice, and suggest that enhancing their beneficial functions may be a treatment strategy in infants at risk for BPD.

  14. Magic Angle Spinning NMR Spectroscopy: A Versatile Technique for Structural and Dynamic Analysis of Solid-Phase Systems

    PubMed Central

    Polenova, Tatyana; Gupta, Rupal; Goldbourt, Amir

    2016-01-01

    Magic Angle Spinning (MAS) NMR spectroscopy is a powerful method for analysis of a broad range of systems, including inorganic materials, pharmaceuticals, and biomacromolecules. The recent developments in MAS NMR instrumentation and methodologies opened new vistas to atomic-level characterization of a plethora of chemical environments previously inaccessible to analysis, with unprecedented sensitivity and resolution. PMID:25794311

  15. 11B and constraints on neutrino oscillations and spectra from neutrino nucleosynthesis.

    PubMed

    Austin, Sam M; Heger, Alexander; Tur, Clarisse

    2011-04-15

    We study the sensitivity to variations in the triple-alpha and 12C(α,γ)16O reaction rates, of the yield of the neutrino-process isotopes 7Li, 11B, 19F, 138La, and 180Ta in core-collapse supernovae. Compared to solar abundances, less than 15% of 7Li, about 25%-80% of 19F, and about half of 138La is produced in these stars. Over a range of ±2σ for each helium-burning rate, 11B is overproduced and the yield varies by an amount larger than the variation caused by the effects of neutrino oscillations. The total 11B yield, however, may eventually provide constraints on supernova neutrino spectra.

  16. One-two step transfer observed in 16O+11B nuclear system

    NASA Astrophysics Data System (ADS)

    Hamada, Sh.; Burtebayev, N.

    2015-06-01

    The angular distribution measurements for 16O ion beam elastically scattered from 11B target of thickness 32.9μg/cm2 at energy 22.4 MeV had been performed in the cyclotron DC-60 INP NNC RK. The previous measurements for 16O+11B nuclear system at energies 27, 30, 32.5 and 35 MeV showed an increase in the differential cross-section at backward angles due to the contribution of cluster transfer. Such transfer process could not be described in terms of optical model (OM); it could be described within the framework of distorted wave Born approximation method implemented in FRESCO code. Both one (5Li) and two-step transfer (proton transfer followed by Alpha transfer) were taken into considerations. We have extracted the spectroscopic amplitude (SA) for the configuration 16O→11B+5Li.

  17. Hypertonicity Compromises Renal Mineralocorticoid Receptor Signaling through Tis11b-Mediated Post-Transcriptional Control

    PubMed Central

    Viengchareun, Say; Lema, Ingrid; Lamribet, Khadija; Keo, Vixra; Blanchard, Anne

    2014-01-01

    The mineralocorticoid receptor (MR) mediates the Na+-retaining action of aldosterone. MR is highly expressed in the distal nephron, which is submitted to intense variations in extracellular fluid tonicity generated by the corticopapillary gradient. We previously showed that post-transcriptional events control renal MR abundance. Here, we report that hypertonicity increases expression of the mRNA-destabilizing protein Tis11b, a member of the tristetraprolin/ZFP36 family, and thereby, decreases MR expression in renal KC3AC1 cells. The 3′-untranslated regions (3′-UTRs) of human and mouse MR mRNA, containing several highly conserved adenylate/uridylate-rich elements (AREs), were cloned downstream of a reporter gene. Luciferase activities of full-length or truncated MR Luc-3′-UTR mutants decreased drastically when cotransfected with Tis11b plasmid, correlating with an approximately 50% shorter half-life of ARE-containing transcripts. Using site-directed mutagenesis and RNA immunoprecipitation, we identified a crucial ARE motif within the MR 3′-UTR, to which Tis11b must bind for destabilizing activity. Coimmunoprecipitation experiments suggested that endogenous Tis11b physically interacts with MR mRNA in KC3AC1 cells, and Tis11b knockdown prevented hypertonicity-elicited repression of MR. Moreover, hypertonicity blunted aldosterone-stimulated expression of glucocorticoid-induced leucine-zipper protein and the α-subunit of the epithelial Na+ channel, supporting impaired MR signaling. Challenging the renal osmotic gradient by submitting mice to water deprivation, diuretic administration, or high-Na+ diet increased renal Tis11b and decreased MR expression, particularly in the cortex, thus establishing a mechanistic pathway for osmotic regulation of MR expression in vivo. Altogether, we uncovered a mechanism by which renal MR expression is regulated through mRNA turnover, a post-transcriptional control that seems physiologically relevant. PMID:24700863

  18. Multisystem Anomalies in Severe Combined Immunodeficiency with Mutant BCL11B.

    PubMed

    Punwani, Divya; Zhang, Yong; Yu, Jason; Cowan, Morton J; Rana, Sadhna; Kwan, Antonia; Adhikari, Aashish N; Lizama, Carlos O; Mendelsohn, Bryce A; Fahl, Shawn P; Chellappan, Ajithavalli; Srinivasan, Rajgopal; Brenner, Steven E; Wiest, David L; Puck, Jennifer M

    2016-12-01

    Background Severe combined immunodeficiency (SCID) is characterized by arrested T-lymphocyte production and by B-lymphocyte dysfunction, which result in life-threatening infections. Early diagnosis of SCID through population-based screening of newborns can aid clinical management and help improve outcomes; it also permits the identification of previously unknown factors that are essential for lymphocyte development in humans. Methods SCID was detected in a newborn before the onset of infections by means of screening of T-cell-receptor excision circles, a biomarker for thymic output. On confirmation of the condition, the affected infant was treated with allogeneic hematopoietic stem-cell transplantation. Exome sequencing in the patient and parents was followed by functional analysis of a prioritized candidate gene with the use of human hematopoietic stem cells and zebrafish embryos. Results The infant had "leaky" SCID (i.e., a form of SCID in which a minimal degree of immune function is preserved), as well as craniofacial and dermal abnormalities and the absence of a corpus callosum; his immune deficit was fully corrected by hematopoietic stem-cell transplantation. Exome sequencing revealed a heterozygous de novo missense mutation, p.N441K, in BCL11B. The resulting BCL11B protein had dominant negative activity, which abrogated the ability of wild-type BCL11B to bind DNA, thereby arresting development of the T-cell lineage and disrupting hematopoietic stem-cell migration; this revealed a previously unknown function of BCL11B. The patient's abnormalities, when recapitulated in bcl11ba-deficient zebrafish, were reversed by ectopic expression of functionally intact human BCL11B but not mutant human BCL11B. Conclusions Newborn screening facilitated the identification and treatment of a previously unknown cause of human SCID. Coupling exome sequencing with an evaluation of candidate genes in human hematopoietic stem cells and in zebrafish revealed that a constitutional

  19. An update on 11B,10B fractionation in the fundamental reaction: 10B(OH)3 + 11B(OH)4- = 11B(OH)3 + 10B(OH)4-

    NASA Astrophysics Data System (ADS)

    Klochko, K.; Tossell, J. A.

    2007-12-01

    It has recently been demonstrated experimentally by Byrne, et al. (2006) and Klochko, et al. (2006) that the equilibrium constant for the isotopic exchange reaction: 10B(OH)3 + 11B(OH)4- = 11B(OH)3 + 10B(OH)4- (1) has a value around 1.027 for seawater at 25°C, for total B concentrations from 0.01 to 0.05 molal. These experimental studies involved essentially the accurate determination of the small pKa difference between the 11B and 10B isotopomers of boric acid. This new equilibrium constant value is significantly higher than the traditional value of 1.0194 from Kakihana, et al. (1977). This result has been obscured in recent controversies (Honisch, et al., 2007). The new value agrees well with the ab initio quantum cluster calculated values of Liu and Tossell (2005) and with the ab initio MD harmonic values of Rustad and Bylaska (2007). We will present additional calculations supporting and extending the study of Liu and Tossell (2005) and will discuss the general unsuitability of methods such as Sanchez-Valle, et al. (2005) which employ experimental spectral data. We have also established that polyborate formation in solutions as concentrated as 0.50 molal total B has little effect on the equilibrium constant. A mechanism is also presented for the interaction of B(OH)3 and B(OH)4- with HCO3- species occurring on the calcite surface. References: Byrne, et al. Deep-Sea Research I (2006) 53, 684-688. Honisch, et al. Geochim. Cosmochim. Acta (2007) 71, 1636-1641. Kakihana, et al. Bull. Chem. Soc. Jpn. (1977) 50, 158-163. Klochko, et al. Earth Planet. Sci. Lett. (2006) 248, 276-285. Liu and Tossell Geochim. Cosmochim. Acta (2005) 69, 3995-4006. Rustad and Bylaska J. Am. Chem. Soc. (2007) 129, 2222-2223. Sanchez-Valle, et al. Geochim. Cosmochim. Acta (2005) 69, 4301-4313.

  20. Instrumentation for solid-state dynamic nuclear polarization with magic angle spinning NMR.

    PubMed

    Rosay, Melanie; Blank, Monica; Engelke, Frank

    2016-03-01

    Advances in dynamic nuclear polarization (DNP) instrumentation and methodology have been key factors in the recent growth of solid-state DNP NMR applications. We review the current state of the art of solid-state DNP NMR instrumentation primarily based on available commercial platforms. We start with a general system overview, including options for microwave sources and DNP NMR probes, and then focus on specific developments for DNP at 100K with magic angle spinning (MAS). Gyrotron microwave sources, passive components to transmit microwaves, the DNP MAS probe, a cooling device for low-temperature MAS, and sample preparation procedures including radicals for DNP are considered.

  1. Instrumentation for solid-state dynamic nuclear polarization with magic angle spinning NMR

    NASA Astrophysics Data System (ADS)

    Rosay, Melanie; Blank, Monica; Engelke, Frank

    2016-03-01

    Advances in dynamic nuclear polarization (DNP) instrumentation and methodology have been key factors in the recent growth of solid-state DNP NMR applications. We review the current state of the art of solid-state DNP NMR instrumentation primarily based on available commercial platforms. We start with a general system overview, including options for microwave sources and DNP NMR probes, and then focus on specific developments for DNP at 100 K with magic angle spinning (MAS). Gyrotron microwave sources, passive components to transmit microwaves, the DNP MAS probe, a cooling device for low-temperature MAS, and sample preparation procedures including radicals for DNP are considered.

  2. Bcl11b: A New Piece to the Complex Puzzle of Amyotrophic Lateral Sclerosis Neuropathogenesis?

    PubMed

    Lennon, Matthew J; Jones, Simon P; Lovelace, Michael D; Guillemin, Gilles J; Brew, Bruce J

    2016-02-01

    Amyotrophic lateral sclerosis (ALS) is an idiopathic, fatal, neurodegenerative disease of the human motor system. The pathogenesis of ALS is a topic of fascinating speculation and experimentation, with theories revolving around intracellular protein inclusions, mitochondrial structural issues, glutamate excitotoxicity and free radical formation. This review explores the rationale for the involvement of a novel protein, B-cell lymphoma/leukaemia 11b (Bcl11b) in ALS. Bcl11b is a multifunctional zinc finger protein transcription factor. It functions as both a transactivator and genetic suppressor, acting both directly, binding to promoter regions, and indirectly, binding to promoter-bound transcription factors. It has essential roles in the differentiation and growth of various cells in the central nervous system, immune system, integumentary system and cardiovascular system, to the extent that Bcl11b knockout mice are incompatible with extra-uterine life. It also has various roles in pathology including the suppression of latent retroviruses, thymic tumourigenesis and neurodegeneration. In particular its functions in neurodevelopment, viral latency and T-cell development suggest potential roles in ALS pathology.

  3. Military Wireless LAN Based on IEEE 802.11b Standard

    DTIC Science & Technology

    2006-12-01

    802.11b Standard RTO-MP-IST-054 P2 - 3 UNCLASSIFIED/UNLIMITED UNCLASSIFIED/UNLIMITED 3.0 POSSIBLE ADAPTATION APROACHES Adaptation of WLAN can...of their flexibility and wide range of possible adaptations. According to their frequency ranges, spreading methods and communication architecture

  4. Mas' Making and Pedagogy: Imagined Possibilities

    ERIC Educational Resources Information Center

    Fournillier, Janice B.

    2009-01-01

    In this article I draw on an ethnographic case study that examined mas' makers' perceptions of the learning/teaching practices at work in the production of costumes for Trinidad and Tobago's annual Carnival celebrations. During the 2005 Carnival season I spent four months in the field, my country of birth, and collected data through participant…

  5. Evaluation of CD11b expression on peripheral blood neutrophils for early detection of neonatal sepsis.

    PubMed

    Adib, Minoo; Ostadi, Vajiheh; Navaei, Fakhri; Saheb Fosoul, Fereshteh; Oreizi, Farzad; Shokouhi, Raheleh; Bakhshiani, Zahra

    2007-06-01

    Neonatal sepsis is a disease of infants who are less than 1 month of age. These infants are clinically ill, and their blood culture are positive for bacteria. The reported incidence of neonatal sepsis for all infants is 1 to 10 per 1000 live births. The mortality rate is 4.2-26%. The clinical signs are not specific and diagnosis of neonatal sepsis is one of the most difficult tasks in clinical medicine. The aim of this work was determination of CD11b sensitivity and specificity for early detection of neonatal sepsis. We studied 65 neonates with gestational age of 27 to 38 weeks who were suspected for sepsis within the 28 days of life. Whole blood was obtained from neonates to determine CD11b expression on peripheral blood neutrophils by flow cytometry. C-Reactive protein (CRP) was measured qualitatively. Neonates were divided into two groups. Classification was based on the result of the blood culture. In the sepsis group all of the neonates (n=8) showed positive blood culture and clinical symptoms. In the suspected group (n=57) the neonates showed clinical signs but blood cultures were negative. Sensitivity and specificity of CD11b were 75%, 100% respectively. Also positive and negative predictive values of CD11b were 100% and 86% respectively. Results of present study and previous studies showed that measurement of neutrophil surface markers can be useful for diagnosis of infection in the early phases. Also, the quantitative measurement of CRP in addition to CD11b further enhances the ability to diagnose infections and improves sensitivity and negative predictive value by 100%.

  6. The promoter of the CD11b gene directs myeloid-specific and developmentally regulated expression.

    PubMed Central

    Shelley, C S; Arnaout, M A

    1991-01-01

    Human CD11b/CD18 (complement receptor type 3) is a member of the beta 2 integrin subfamily which also includes the heterodimers CD11a/CD18 and CD11c/CD18. The CD11 molecules and the common CD18 are the products of different genes that exhibit distinct though overlapping patterns of tissue- and developmental-specific expression. Whereas expression of CD11b and CD11c is almost exclusively restricted to cells of the myeloid lineage, that of CD11a and CD18 is panleukocytic. To begin to understand the mechanisms by which expression of these gene products is restricted to leukocytes and leukocyte subpopulations and to elucidate the mechanisms by which their expression is coordinated, we have cloned and characterized the promoter region of the CD11b gene. A single transcription initiation site has been identified and the region extending 242 base pairs upstream and 71 base pairs downstream of this site has been shown to be sufficient to direct tissue-, cell-, and development-specific expression in vitro, which mimics that of the CD11b gene in vivo. Within this region there are potential binding sites for transcription factors known to be involved in hematopoietic-specific and phorbol ester-inducible gene expression. Further analysis of this region of the CD11b gene and comparison with the promoters of the CD11a, CD11c, and CD18 genes should lead to significant insights into the molecular mechanisms by which these genes are regulated during hematopoietic development and upon activation. Images PMID:1683702

  7. TNFRSF11B gene polymorphisms, bone mineral density, and fractures in Slovak postmenopausal women.

    PubMed

    Boroňová, Iveta; Bernasovská, Jarmila; Mačeková, Soňa; Petrejčíková, Eva; Tomková, Zlatica; Kľoc, Ján; Poráčová, Janka; Blaščáková, Marta Mydlárová; Litavcová, Eva

    2015-02-01

    Osteoporosis is a common disease that is characterized by low bone mineral density (BMD), deterioration in bone microarchitecture, and increased fracture risk. Due to its important role in bone biology, the TNFRSF11B gene, coding for OPG, has been considered as a candidate gene for osteoporosis. In this study, single nucleotide polymorphisms (SNPs) A163G, T245G, and G1181C (rs3102735, rs3134069, and rs2073618, respectively) within the TNFRSF11B gene were studied for association with BMD and fracture incidence in a cohort of 327 postmenopausal Slovak women. Genomic DNA was extracted and purified from peripheral blood leukocytes by the commercial kit JetQuick (Genomed GmbH, Germany) using a standard protocol. Genotyping was performed using the Custom TaqMan® SNP Genotyping Assays. The lumbar L1-L4 spine BMD (g/cm(2)) and T-score in the subgroup of Slovak postmenopausal women with osteoporotic fractures were significantly lower than those in the subgroup of women without fracture (p = 0.0025; p = 0.0009). We identified the T245G (rs3134069) polymorphism in the TNFRSF11B gene associated with osteoporotic fractures (vertebral fractures: p = 0.0320; non-vertebral fractures: p = 0.0005; all fractures: 0.0000). The polymorphism T245G (rs3134069) in the TNFRSF11B gene could be used together with other genetic markers to identify individuals at high risk of osteoporotic fractures. The results from the present study provided more evidence to reveal the role of TNFRSF11B gene polymorphisms in BMD and the risk of osteoporotic fractures.

  8. Activated CD11b+ CD15+ Granulocytes Increase in the Blood of Patients with Uveal Melanoma

    PubMed Central

    McKenna, Kyle C.; Beatty, Kelly M.; Bilonick, Richard A.; Schoenfield, Lynn; Lathrop, Kira L.; Singh, Arun D.

    2017-01-01

    Purpose To determine whether activated CD11b+ CD15+ granulocytes increase in the blood of patients with uveal melanoma. Methods Peripheral blood mononuclear cells (PBMCs) were isolated by density gradient centrifugation from the blood of patients with primary choroidal/ciliochoroidal uveal melanomas (six women, four men; age range, 46–91 years) and healthy control donors (14 women, 10 men; age range, 50 – 81 years). The expression of CD15 and CD68 on CD11b+ myeloid cells within PBMCs and primary uveal melanomas was evaluated by flow cytometry. CD3ζ chain expression by CD3ε+ T cells in PBMCs and within primary uveal melanomas was measured as an indirect indication of T-cell function. Results The percentage of CD11b+ cells in PBMCs of patients with uveal melanoma increased 1.8-fold in comparison to healthy donors and comprised three subsets: CD68 negative CD15+ granulocytes, which increased 4.1-fold; CD68− CD15− cells, which increased threefold; and CD68+ CD15low cells, which were unchanged. A significant (2.7-fold) reduction in CD3ζ chain expression on CD3ε+ T cells, a marker of T-cell dysfunction, was observed in PBMCs of patients with uveal melanoma in comparison with healthy control subjects and correlated significantly with the percentage of CD11b+ cells in PBMCs. CD3ζ chain expression on T cells within primary tumors was equivalent to CD3ζ expression in PBMCs of the same patient in four of five patients analyzed. Conclusions Activated CD11b+ CD15+ granulocytes expand in the blood of patients with uveal melanoma and may contribute to immune evasion by ocular tumors by inhibiting T-cell function via decreasing CD3ζ chain expression. PMID:19369244

  9. Construction of 3D models of the CYP11B family as a tool to predict ligand binding characteristics

    PubMed Central

    Sanders, Marijn P. A.; Pieterse, Koen; Hilbers, Peter A. J.; Plate, Ralf; Custers, Erica; de Gooyer, Marcel; Smits, Jos F. M.; Beugels, Ilona; Emmen, Judith; Ottenheijm, Harry C. J.; Leysen, Dirk; Hermans, J. J. R.

    2007-01-01

    Aldosterone is synthesised by aldosterone synthase (CYP11B2). CYP11B2 has a highly homologous isoform, steroid 11β-hydroxylase (CYP11B1), which is responsible for the biosynthesis of aldosterone precursors and glucocorticoids. To investigate aldosterone biosynthesis and facilitate the search for selective CYP11B2 inhibitors, we constructed three-dimensional models for CYP11B1 and CYP11B2 for both human and rat. The models were constructed based on the crystal structure of Pseudomonas Putida CYP101 and Oryctolagus Cuniculus CYP2C5. Small steric active site differences between the isoforms were found to be the most important determinants for the regioselective steroid synthesis. A possible explanation for these steric differences for the selective synthesis of aldosterone by CYP11B2 is presented. The activities of the known CYP11B inhibitors metyrapone, R-etomidate, R-fadrazole and S-fadrazole were determined using assays of V79MZ cells that express human CYP11B1 and CYP11B2, respectively. By investigating the inhibitors in the human CYP11B models using molecular docking and molecular dynamics simulations we were able to predict a similar trend in potency for the inhibitors as found in the in vitro assays. Importantly, based on the docking and dynamics simulations it is possible to understand the enantioselectivity of the human enzymes for the inhibitor fadrazole, the R-enantiomer being selective for CYP11B2 and the S-enantiomer being selective for CYP11B1. PMID:17646925

  10. Fundamental Science Tools for Geologic Carbon Sequestration and Mineral Carbonation Chemistry: In Situ Magic Angle Spinning (MAS) Nuclear Magnetic Resonance

    NASA Astrophysics Data System (ADS)

    Hoyt, D. W.; Turcu, R. V.; Sears, J. A.; Rosso, K. M.; Burton, S. D.; Kwak, J.; Felmy, A. R.; Hu, J.

    2010-12-01

    GCS is one of the most promising ways of mitigating atmospheric greenhouse gases. Mineral carbonation reactions are potentially important to the long-term sealing effectiveness of caprock but remain poorly predictable, particularly reactions occurring in low-water supercritical CO2(scCO2)-dominated environments where the chemistry has not been adequately explored. In situ probes that provide molecular-level information is desirable for investigating mechanisms and rates of GCS mineral carbonation reactions. MAS-NMR is a powerful tool for obtaining detailed molecular structure and dynamics information of a system regardless whether the system is in a solid, a liquid, a gaseous, or a supercritical state, or a mixture thereof. However, MAS NMR under scCO2 conditions has never been realized due to the tremendous technical difficulties of achieving and maintaining high pressure within a fast spinning MAS rotor. In this work, we report development of a unique high pressure MAS NMR capability, and its application to mineral carbonation chemistry in scCO2 under geologically relevant temperatures and pressures. Our high pressure MAS rotor has successfully maintained scCO2 conditions with minimal leakage over a period of 72 hours. Mineral carbonation reactions of a model magnesium silicate (forsterite) reacted with 96 bars scCO2 containing varying amounts of H2O (both below and above saturation of the scCO2) were investigated at 50○C. Figure 1 shows typical in situ 13C MAS NMR spectra demonstrating that the peaks corresponding to the reactants, intermediates, and the magnesium carbonation products are all observed in a single spectrum. For example, the scCO2 peak is located at 126.1 ppm. Reaction intermediates include the aqueous species HCO3-(160 ppm), partially hydrated/hydroxylated magnesium carbonates(166-168 ppm), and can easily be distinguished from final product magnesite(170 ppm). The new capability and this model mineral carbonation process will be overviewed in

  11. Improved Superconducting properties in the Mg(11)B2 low activation superconductor prepared by low-temperature sintering.

    PubMed

    Cheng, Fang; Liu, Yongchang; Ma, Zongqing; Shahriar Al Hossain, M; Somer, M

    2016-05-05

    Mg(11)B2 has a great application prospect in the superconducting coils for fusion reactor as the "low activation superconductors". The un-doped Mg(11)B2 and Cu-doped Mg(11)B2 bulks using (11)B as a boron precursor were fabricated by low-temperature sintering in present work. It was found that the prepared Mg(11)B2 low activation superconductors exhibit better Jc performance than all of other Mg(11)B2 samples reported in previous studies. As for Cu doped Mg(11)B2, minor Cu addition can obviously improve the Mg(11)B2 grain crystallization and reduce the amount of MgO impurity. Hence, improved grain connectivity and higher Jc at low fields is obtained in Cu doped Mg(11)B2 samples. For un-doped samples, refined grains and more MgO impurity with proper size brought about more flux pinning centers, resulting in better Jc performance at high fields.

  12. [Isolation and functional analysis of GsTIFY11b relevant to salt and alkaline stress from Glycine soja].

    PubMed

    Zhu, Dan; Bai, Xi; Zhu, Yan-Ming; Cai, Hua; Li, Yong; Ji, Wei; Chen, Chao; An, Lin; Zhu, Yi

    2012-02-01

    Using homologous cloning and RT-PCR technology, we isolated a novel TIFY family gene, GsTIFY11b, from Glycine soja L. G07256, a species that is tolerant to saline and alkaline environments. Phylogenetic analysis indicated that GsTIFY11b was closely related to AtTIFY11a with 56% similarity in amino acid identity. Protein sequence analysis showed that GsTIFY11b protein also had conserved TIFY domain, N-terminal domain, and a C-terminal Jas motif. Quantitative realtime PCR analysis indicated that the expression of GsTIFY11b was induced by both saline and alkaline stresses. Two homozygous GsTIFY11b over-expressing transgenic Arabidopsis lines were obtained. Phenotypic analysis of the transgenic and wild-type Arabidopsis indicated that over-expressing GsTIFY11b in Arabidopsis did not enhance plant tolerance to saline and alkaline stresses, whereas it showed an increased sensitivity to saline stress during seed germination and seedling development. Expression analysis of saline stress response marker genes in transgenic and wild-type plants under stress condition indicated that GsTIFY11b regulated the expression of RD29B, KIN1, and DREB. The transient expression of a GsTIFY11b-GFP fusion protein in onion epidermal cells showed that GsTIFY11b was localized to the nucleus, suggesting a role as a transcriptional regulator in the saline stress response pathway.

  13. Improved Superconducting properties in the Mg11B2 low activation superconductor prepared by low-temperature sintering

    PubMed Central

    Cheng, Fang; Liu, Yongchang; Ma, Zongqing; Shahriar Al Hossain, M.; Somer, M.

    2016-01-01

    Mg11B2 has a great application prospect in the superconducting coils for fusion reactor as the “low activation superconductors”. The un-doped Mg11B2 and Cu-doped Mg11B2 bulks using 11B as a boron precursor were fabricated by low-temperature sintering in present work. It was found that the prepared Mg11B2 low activation superconductors exhibit better Jc performance than all of other Mg11B2 samples reported in previous studies. As for Cu doped Mg11B2, minor Cu addition can obviously improve the Mg11B2 grain crystallization and reduce the amount of MgO impurity. Hence, improved grain connectivity and higher Jc at low fields is obtained in Cu doped Mg11B2 samples. For un-doped samples, refined grains and more MgO impurity with proper size brought about more flux pinning centers, resulting in better Jc performance at high fields. PMID:27149682

  14. Performance Evolution of IEEE 802.11b Wireless Local Area Network

    NASA Astrophysics Data System (ADS)

    Malik, Deepak; Singhal, Ankur

    2011-12-01

    The Wireless network can be employed to connect wired network to the wireless network. Wireless local area networks (WLAN) are more bandwidth limited as compared to the wired networks because they rely on an inexpensive, but error prone, physical medium (air). Hence it is important to evaluate their performance. This paper presents a study of IEEE 802.11b wireless LAN (WLAN). The performance evaluation has been presented via a series of test with different parameters such as data rate, different number of nodes and physical characteristics. The different qualities of service parameter are chosen to be throughput, media access delay and dropped data packets. The simulation results show that an IEEE 802.11b WLAN can support up to 60 clients with modest throughput. Finally the results are compared to evaluate the performance of wireless local networks.

  15. Boron and diagenesis: Questioning the fidelity of Snowball δ11B excursions

    NASA Astrophysics Data System (ADS)

    Foster, G. L.; Stewart, J.; Gutjahr, M.; Pearce, F.; Swart, P. K.

    2014-12-01

    Large negative carbon (δ13C) and boron (δ11B) isotope excursions (both >6‰) within the widely distributed Neoproterozoic "Snowball Earth" cap carbonates are interpreted as evidence for considerable perturbation of the carbon cycle and the associated reduction, then recovery of global ocean pH. Yet, before conclusive interpretations may be drawn, isotopic data must first be shown to be primary in origin and non-diagenetic. Recent studies of Quaternary carbonate platform sediments from a number of locations worldwide reveal δ13C excursions of similar magnitude and distribution to the "Snowball Earth" excursions. However, these recent analogues were formed following eustatic sea level fall and exposure of recent carbonates to meteoric diagenesis (Swart and Kennedy, 2012). Here we present δ11B and B/Ca data from Pleistocene-aged carbonate platform sediments recovered by the Clino Core from the Bahamas to examine the effects of diagenesis on the boron system. We find that within the interval of meteoric diagenesis the δ11B of bulk carbonate is substantially reduced by approximately 6‰ in conjunction with a drop in B/Ca of 90%. These isotopic and elemental down-core patterns are strikingly similar to those reported for δ11B and B/Ca in the cap carbonates of the Neoproterozoic snowball Earth events (Kasemann et al., 2005; Kasemann et al., 2010). Our results may therefore question the primary nature of "Snowball Earth" isotope excursions. We recommend more rigorous assessment of the diagenetic history of these ancient carbonates to ensure palaeoclimatological interpretations are robust.

  16. Conditional Deletion of Hsd11b2 in the Brain Causes Salt Appetite and Hypertension

    PubMed Central

    Evans, Louise C.; Ivy, Jessica R.; Wyrwoll, Caitlin; McNairn, Julie A.; Menzies, Robert I.; Christensen, Thorbjørn H.; Al-Dujaili, Emad A.S.; Kenyon, Christopher J.; Mullins, John J.; Seckl, Jonathan R.; Holmes, Megan C.

    2016-01-01

    Background— The hypertensive syndrome of Apparent Mineralocorticoid Excess is caused by loss-of-function mutations in the gene encoding 11β-hydroxysteroid dehydrogenase type 2 (11βHSD2), allowing inappropriate activation of the mineralocorticoid receptor by endogenous glucocorticoid. Hypertension is attributed to sodium retention in the distal nephron, but 11βHSD2 is also expressed in the brain. However, the central contribution to Apparent Mineralocorticoid Excess and other hypertensive states is often overlooked and is unresolved. We therefore used a Cre-Lox strategy to generate 11βHSD2 brain-specific knockout (Hsd11b2.BKO) mice, measuring blood pressure and salt appetite in adults. Methods and Results— Basal blood pressure, electrolytes, and circulating corticosteroids were unaffected in Hsd11b2.BKO mice. When offered saline to drink, Hsd11b2.BKO mice consumed 3 times more sodium than controls and became hypertensive. Salt appetite was inhibited by spironolactone. Control mice fed the same daily sodium intake remained normotensive, showing the intrinsic salt resistance of the background strain. Dexamethasone suppressed endogenous glucocorticoid and abolished the salt-induced blood pressure differential between genotypes. Salt sensitivity in Hsd11b2.BKO mice was not caused by impaired renal sodium excretion or volume expansion; pressor responses to phenylephrine were enhanced and baroreflexes impaired in these animals. Conclusions— Reduced 11βHSD2 activity in the brain does not intrinsically cause hypertension, but it promotes a hunger for salt and a transition from salt resistance to salt sensitivity. Our data suggest that 11βHSD2-positive neurons integrate salt appetite and the blood pressure response to dietary sodium through a mineralocorticoid receptor–dependent pathway. Therefore, central mineralocorticoid receptor antagonism could increase compliance to low-sodium regimens and help blood pressure management in cardiovascular disease. PMID

  17. Induction of Atrial Fibrillation by Neutrophils Critically Depends on CD11b/CD18 Integrins

    PubMed Central

    Remane, Lisa; Mollenhauer, Martin; Rudolph, Volker; Rudolph, Tanja K.; Andrié, René P.; Stöckigt, Florian; Schrickel, Jan W.; Ravekes, Thorben; Deuschl, Florian; Nickenig, Georg; Willems, Stephan; Baldus, Stephan; Klinke, Anna

    2014-01-01

    Background Recent observational clinical and ex-vivo studies suggest that inflammation and in particular leukocyte activation predisposes to atrial fibrillation (AF). However, whether local binding and extravasation of leukocytes into atrial myocardium is an essential prerequisite for the initiation and propagation of AF remains elusive. Here we investigated the role of atrial CD11b/CD18 mediated infiltration of polymorphonuclear neutrophils (PMN) for the susceptibility to AF. Methods and Results C57bl/6J wildtype (WT) and CD11b/CD18 knock-out (CD11b−/−) mice were treated for 14 days with subcutaneous infusion of angiotensin II (Ang II), a known stimulus for PMN activation. Atria of Ang II-treated WT mice were characterized by increased PMN infiltration assessed in immunohistochemically stained sections. In contrast, atrial sections of CD11b−/− mice lacked a significant increase in PMN infiltration upon Ang II infusion. PMN infiltration was accompanied by profoundly enhanced atrial fibrosis in Ang II treated WT as compared to CD11b−/− mice. Upon in-vivo electrophysiological investigation, Ang II treatment significantly elevated the susceptibility for AF in WT mice if compared to vehicle treated animals given an increased number and increased duration of AF episodes. In contrast, animals deficient of CD11b/CD18 were entirely protected from AF induction. Likewise, epicardial activation mapping revealed decreased electrical conduction velocity in atria of Ang II treated WT mice, which was preserved in CD11b−/− mice. In addition, atrial PMN infiltration was enhanced in atrial appendage sections of patients with persistent AF as compared to patients without AF. Conclusions The current data critically link CD11b-integrin mediated atrial PMN infiltration to the formation of fibrosis, which promotes the initiation and propagation of AF. These findings not only reveal a mechanistic role of leukocytes in AF but also point towards a potential novel avenue of

  18. Effects of CD11b/18 monoclonal antibody on rats with permanent middle cerebral artery occlusion.

    PubMed Central

    Garcia, J. H.; Liu, K. F.; Bree, M. P.

    1996-01-01

    The progression of a lesion from ischemic injury to infarct, after the permanent occlusion of a middle cerebral artery, may be influenced by the influx of leukocytes into the ischemic territory. We aimed to evaluate the effectiveness of treating rats that had permanent middle cerebral artery occlusion with a single dose of an anti-CD11b/18 monoclonal antibody injected 1 hour after the arterial occlusion. To mimic the clinical situation of patients with ischemic strokes who may be treated within 1 hour of the ischemic event, the artery remained occluded. Forty-one adult Wistar rats had permanent middle cerebral artery occlusion, and one was subjected to a sham operation. One hour later, 22 rats received CD11b/18 monoclonal antibody and an additional 20 were injected either with a nonspecific antibody (n = 10) or a buffer solution (n = 10). Experiments were terminated at intervals ranging 12 to 96 hours after the arterial occlusion. Endpoints included neurological testing, daily evaluation of body weight, counts of white blood cells in the peripheral blood, measurement of the area of pallor in the ischemic hemisphere, counts of necrotic neurons, and counts of leukocytes sequestered in the ischemic hemisphere. In experiments terminated 12 hours after the arterial occlusion (n = 4), there were fewer necrotic neurons in the group treated with the CD11b/18 monoclonal antibody compared with the two controls (P < .05), but this difference was not reflected in the neurological scores. Numbers of necrotic neurons in experiments terminated > 12 hours later were not different among the three subgroups. White blood cell counts in peripheral blood were lower in animals with arterial occlusion injected with the monoclonal antibody CD11b/18 (P < .05); numbers of leukocytes sequestered in the ischemic hemisphere were not different in the three groups. Neither changes in body weight nor in the volume of the area of pallor were significantly different among the three groups. Images

  19. From precursors to non-oxide ceramics: Pyrolytic mechanisms studied by NMR

    SciTech Connect

    Sigmund, W.M.; Aldinger, F.; Feike, M.; Spiess, H.W.

    1996-12-31

    The pyrolysis of a poly ethylsilazane was studied using a CO{sub 2}-laser beam heated solid state MAS-NMR probe head. Chemical structures of the intermediate stages could be identified. The analogy of the pyrolysis evolution for the following two different methods could be shown: (A) in an inert gas furnace conventionally prepared and (B) laser irradiated in the NMR probe head under magic-angle spinning (MAS) conditions. Samples prepared by method A were studied by {sup 29}Si MAS-NMR and samples prepared by method B were studied with an appropriate cross polarization time by {sup 29}Si CP-MAS-NMR. Both experiments showed the same mechanisms for the pyrolysis as the polymer is transformed into a Si{sub 3}N{sub 4}/C ceramic.

  20. Linking CD11b+ Dendritic Cells and Natural Killer T Cells to Plaque Inflammation in Atherosclerosis

    PubMed Central

    Rombouts, Miche; Ammi, Rachid; Van Brussel, Ilse; Roth, Lynn; De Winter, Benedicte Y.; Vercauteren, Sven R.; Hendriks, Jeroen M. H.; Lauwers, Patrick; Van Schil, Paul E.; De Meyer, Guido R. Y.; Fransen, Erik; Cools, Nathalie; Schrijvers, Dorien M.

    2016-01-01

    Atherosclerosis remains the leading cause of death and disability in our Western society. To investigate whether the dynamics of leukocyte (sub)populations could be predictive for plaque inflammation during atherosclerosis, we analyzed innate and adaptive immune cell distributions in blood, plaques, and lymphoid tissue reservoirs in apolipoprotein E-deficient (ApoE−/−) mice and in blood and plaques from patients undergoing endarterectomy. Firstly, there was predominance of the CD11b+ conventional dendritic cell (cDC) subset in the plaque. Secondly, a strong inverse correlation was observed between CD11b+ cDC or natural killer T (NKT) cells in blood and markers of inflammation in the plaque (including CD3, T-bet, CCR5, and CCR7). This indicates that circulating CD11b+ cDC and NKT cells show great potential to reflect the inflammatory status in the atherosclerotic plaque. Our results suggest that distinct changes in inflammatory cell dynamics may carry biomarker potential reflecting atherosclerotic lesion progression. This not only is crucial for a better understanding of the immunopathogenesis but also bares therapeutic potential, since immune cell-based therapies are emerging as a promising novel strategy in the battle against atherosclerosis and its associated comorbidities. The cDC-NKT cell interaction in atherosclerosis serves as a good candidate for future investigations. PMID:27051078

  1. Detection of the Secondary Eclipse of Exoplanet HAT P-11b

    NASA Technical Reports Server (NTRS)

    Barry, R. K.; Deming, L. D.; Bakos, G.; Harrington, J.; Madhusudhan, N.; Noyes, R.; Seager, S.

    2010-01-01

    We have successfully conducted secondary eclipse observations of exoplanet HAT-P-11b using the Spitzer Space Telescope. HAT-P-11b was, until very recently, the smallest transiting extrasolar planet yet found and one of only two known exo-Neptunes. We observed the system at 3.6 microns for a period of 22 hours centered on the anticipated secondary eclipse time, to detect the eclipse and determine its phase. Having detected the secondary eclipse, we are at present making a more focused series of observations in both the 3.6 and 4.5 micron bands to fully characterize it. HAT-P-11b has a period of 4.8878 days, radius of 0.422 RJ, mass of 0.081 MJ and semi-major axis 0.053 AU. Measurements of the secondary eclipse will serve to clarify two key issues; 1) the planetary brightness temperature and the nature of its atmosphere, and 2) the eccentricity of its orbit, with implications for its dynamical evolution. A precise determination of the orbit phase for the secondary eclipse will also be of great utility for Kepler observations of this system at visible wavelengths.

  2. Wireless Coexistence and EMC of Bluetooth and 802.11b Devices in Controlled Laboratory Settings.

    PubMed

    Seidman, Seth; Kainz, Wolfgang; Ruggera, Paul; Mendoza, Gonzalo

    2011-01-01

    This paper presents experimental testing that has been performed on wireless communication devices as victims of electromagnetic interference (EMI). Wireless victims included universal serial bus (USB) network adapters and personal digital assistants (PDAs) equipped with IEEE 802.11b and Bluetooth technologies. The experimental data in this paper was gathered in an anechoic chamber and a gigahertz transverse electromagnetic (GTEM) cell to ensure reliable and repeatable results. This testing includes: Electromagnetic compatibility (EMC) testing performed in accordance with IEC 60601-1-2, an in-band sweep of EMC testing, and coexistence testing. The tests in this study show that a Bluetooth communication was able to coexist with other Bluetooth devices with no decrease in throughput and no communication breakdowns. However, testing revealed a significant decrease in throughput and increase in communication breakdowns when an 802.11b source is near an 802.11b victim. In a hospital setting decreased throughput and communication breakdowns can cause wireless medical devices to fail. It is therefore vital to have an understanding of the effect EMI can have on wireless communication devices.

  3. Discovery of the secondary eclipse of HAT-P-11 b

    NASA Astrophysics Data System (ADS)

    Huber, K. F.; Czesla, S.; Schmitt, J. H. M. M.

    2017-01-01

    We report the detection of the secondary eclipse of HAT-P-11 b, a Neptune-sized planet orbiting an active K4 dwarf. Using all available short-cadence data of the Kepler mission, we derive refined planetary ephemeris increasing their precision by more than an order of magnitude. Our simultaneous primary and secondary transit modeling results in improved transit and orbital parameters. In particular, the precise timing of the secondary eclipse allows to pin down the orbital eccentricity to . The secondary eclipse depth of ppm corresponds to a 5.5σ detection and results in a geometric albedo of 0.39 ± 0.07 for HAT-P-11 b, close to Neptune's value, which may indicate further resemblances between these two bodies. Due to the substantial orbital eccentricity, the planetary equilibrium temperature is expected to change significantly with orbital position and ought to vary between 630 K and 950 K, depending on the details of heat redistribution in the atmosphere of HAT-P-11 b.

  4. On the use of ultracentrifugal devices for routine sample preparation in biomolecular magic-angle-spinning NMR.

    PubMed

    Mandal, Abhishek; Boatz, Jennifer C; Wheeler, Travis B; van der Wel, Patrick C A

    2017-02-22

    A number of recent advances in the field of magic-angle-spinning (MAS) solid-state NMR have enabled its application to a range of biological systems of ever increasing complexity. To retain biological relevance, these samples are increasingly studied in a hydrated state. At the same time, experimental feasibility requires the sample preparation process to attain a high sample concentration within the final MAS rotor. We discuss these considerations, and how they have led to a number of different approaches to MAS NMR sample preparation. We describe our experience of how custom-made (or commercially available) ultracentrifugal devices can facilitate a simple, fast and reliable sample preparation process. A number of groups have since adopted such tools, in some cases to prepare samples for sedimentation-style MAS NMR experiments. Here we argue for a more widespread adoption of their use for routine MAS NMR sample preparation.

  5. Angiotensin (1-7) induces MAS receptor internalization.

    PubMed

    Gironacci, Mariela M; Adamo, Hugo P; Corradi, Gerardo; Santos, Robson A; Ortiz, Pablo; Carretero, Oscar A

    2011-08-01

    Angiotensin (Ang) (1-7) is the endogenous ligand for the G protein-coupled receptor Mas, a receptor associated with cardiac, renal, and cerebral protective responses. Physiological evidence suggests that Mas receptor (MasR) undergoes agonist-dependent desensitization, but the underlying molecular mechanism regulating receptor activity is unknown. We investigated the hypothesis that MasR desensitizes and internalizes on stimulation with Ang-(1-7). For this purpose, we generated a chimera between the MasR and the yellow fluorescent protein (YFP; MasR-YFP). MasR-YFP-transfected HEK 293T cells were incubated with Ang-(1-7), and the relative cellular distribution of MasR-YFP was observed by confocal microscopy. In resting cells, MasR-YFP was mostly localized to the cell membrane. Ang-(1-7) induced a redistribution of MasR-YFP to intracellular vesicles of various sizes after 5 minutes. Following the time course of [(125)I]Ang-(1-7) endocytosis, we observed that half of MasR-YFP underwent endocytosis after 10 minutes, and this was blocked by a MasR antagonist. MasR-YFP colocalized with Rab5, the early endosome antigen 1, and the adaptor protein complex 2, indicating that the R is internalized through a clathrin-mediated pathway and targeted to early endosomes after Ang-(1-7) stimulation. A fraction of MasR-YFP also colocalized with caveolin 1, suggesting that at some point MasR-YFP traverses caveolin 1-positive compartments. In conclusion, MasR undergoes endocytosis on stimulation with Ang-(1-7), and this event may explain the desensitization of MasR responsiveness. In this way, MasR activity and density may be tightly controlled by the cell.

  6. 17 CFR 274.11b - Form N-3, registration statement of separate accounts organized as management investment companies.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... statement of separate accounts organized as management investment companies. 274.11b Section 274.11b... accounts organized as management investment companies. Form N-3 shall be used as the registration statement... offer variable annuity contracts to register as management investment companies. This form shall also...

  7. 17 CFR 274.11b - Form N-3, registration statement of separate accounts organized as management investment companies.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... statement of separate accounts organized as management investment companies. 274.11b Section 274.11b... accounts organized as management investment companies. Form N-3 shall be used as the registration statement... offer variable annuity contracts to register as management investment companies. This form shall also...

  8. BCL11B/CTIP2 is highly expressed in GABAergic interneurons of the mouse somatosensory cortex.

    PubMed

    Nikouei, Kasra; Muñoz-Manchado, Ana B; Hjerling-Leffler, Jens

    2016-01-01

    In the nervous system, BCL11B is crucial for the development of deep layer corticospinal projection neurons and striatal medium spiny neurons and is often used as a marker for the aforementioned cell types. However, the expression of BCL11B in subtypes of non-excitatory neurons in the primary somatosensory cortex (S1) has not been reported in the mouse. In this study we show that BCL11B is extensively expressed in S1 GABAergic interneurons, throughout the three main subgroups (somatostatin-, parvalbumin- and 5HT3a-expresssing). Almost all BCL11B positive cells in the upper S1 layers were GABAergic interneurons and surprisingly, almost 40% of the BCL11B positive neurons in layer V were GABAergic interneurons. Single cell mRNA sequencing data revealed higher Bcl11b expression in S1 interneurons compared to deep layer pyramidal neurons. The highest levels of Bcl11b expression were found within the 5HT3a population, specifically in putative neurogliaform interneuron subclasses (5HT3a-positive but not expressing vasoactive intestinal peptide). In the light of our findings we suggest caution using BCL11B as a single marker to identify neurons.

  9. Magic angle spinning NMR of paramagnetic proteins.

    PubMed

    Knight, Michael J; Felli, Isabella C; Pierattelli, Roberta; Emsley, Lyndon; Pintacuda, Guido

    2013-09-17

    Metal ions are ubiquitous in biochemical and cellular processes. Since many metal ions are paramagnetic due to the presence of unpaired electrons, paramagnetic molecules are an important class of targets for research in structural biology and related fields. Today, NMR spectroscopy plays a central role in the investigation of the structure and chemical properties of paramagnetic metalloproteins, linking the observed paramagnetic phenomena directly to electronic and molecular structure. A major step forward in the study of proteins by solid-state NMR came with the advent of ultrafast magic angle spinning (MAS) and the ability to use (1)H detection. Combined, these techniques have allowed investigators to observe nuclei that previously were invisible in highly paramagnetic metalloproteins. In addition, these techniques have enabled quantitative site-specific measurement of a variety of long-range paramagnetic effects. Instead of limiting solid-state NMR studies of biological systems, paramagnetism provides an information-rich phenomenon that can be exploited in these studies. This Account emphasizes state-of-the-art methods and applications of solid-state NMR in paramagnetic systems in biological chemistry. In particular, we discuss the use of ultrafast MAS and (1)H-detection in perdeuterated paramagnetic metalloproteins. Current methodology allows us to determine the structure and dynamics of metalloenzymes, and, as an example, we describe solid-state NMR studies of microcrystalline superoxide dismutase, a 32 kDa dimer. Data were acquired with remarkably short times, and these experiments required only a few milligrams of sample.

  10. Moderate MAS enhances local (1)H spin exchange and spin diffusion.

    PubMed

    Roos, Matthias; Micke, Peter; Saalwächter, Kay; Hempel, Günter

    2015-11-01

    Proton NMR spin-diffusion experiments are often combined with magic-angle spinning (MAS) to achieve higher spectral resolution of solid samples. Here we show that local proton spin diffusion can indeed become faster at low (<10 kHz) spinning rates as compared to static conditions. Spin diffusion under static conditions can thus be slower than the often referred value of 0.8 nm(2)/ms, which was determined using slow MAS (Clauss et al., 1993). The enhancement of spin diffusion by slow MAS relies on the modulation of the orientation-dependent dipolar couplings during sample rotation and goes along with transient level crossings in combination with dipolar truncation. The experimental finding and its explanation is supported by density matrix simulations, and also emphasizes the sensitivity of spin diffusion to the local coupling topology. The amplification of spin diffusion by slow MAS cannot be explained by any model based on independent spin pairs; at least three spins have to be considered.

  11. Performance of RINEPT is amplified by dipolar couplings under ultrafast MAS conditions.

    PubMed

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy

    2014-06-01

    The refocused insensitive nuclei enhanced by polarization transfer (RINEPT) technique is commonly used for heteronuclear polarization transfer in solution and solid-state NMR spectroscopy. Suppression of dipolar couplings, either by fast molecular motions in solution or by a combination of MAS and multiple pulse sequences in solids, enables the polarization transfer via scalar couplings. However, the presence of unsuppressed dipolar couplings could alter the functioning of RINEPT, particularly under fast/ultrafast MAS conditions. In this study, we demonstrate, through experiments on rigid solids complemented by numerical simulations, that the polarization transfer efficiency of RINEPT is dependent on the MAS frequency. In addition, we show that heteronuclear dipolar coupling is the dominant factor in the polarization transfer, which is strengthened by the presence of (1)H-(1)H dipolar couplings. In fact, the simultaneous presence of homonuclear and heteronuclear dipolar couplings is the premise for the polarization transfer by RINEPT, whereas the scalar coupling plays an insignificant role under ultrafast MAS conditions on rigid solids. Our results additionally reveal that the polarization transfer efficiency decreases with the increasing duration of RF pulses used in the RINEPT sequence.

  12. CD11b+Ly6G− myeloid cells mediate mechanical inflammatory pain hypersensitivity

    PubMed Central

    Ghasemlou, Nader; Chiu, Isaac M.; Julien, Jean-Pierre; Woolf, Clifford J.

    2015-01-01

    Pain hypersensitivity at the site of inflammation as a result of chronic immune diseases, pathogenic infection, and tissue injury is a common medical condition. However, the specific contributions of the innate and adaptive immune system to the generation of pain during inflammation have not been systematically elucidated. We therefore set out to characterize the cellular and molecular immune response in two widely used preclinical models of inflammatory pain: (i) intraplantar injection of complete Freund’s adjuvant (CFA) as a model of adjuvant- and pathogen-based inflammation and (ii) a plantar incisional wound as a model of tissue injury-based inflammation. Our findings reveal differences in temporal patterns of immune cell recruitment and activation states, cytokine production, and pain in these two models, with CFA causing a nonresolving granulomatous inflammatory response whereas tissue incision induced resolving immune and pain responses. These findings highlight the significant differences and potential clinical relevance of the incisional wound model compared with the CFA model. By using various cell-depletion strategies, we find that, whereas lymphocyte antigen 6 complex locus G (Ly)6G+CD11b+ neutrophils and T-cell receptor (TCR) β+ T cells do not contribute to the development of thermal or mechanical pain hypersensitivity in either model, proliferating CD11b+Ly6G− myeloid cells were necessary for mechanical hypersensitivity during incisional pain, and, to a lesser extent, CFA-induced inflammation. However, inflammatory (CCR2+Ly6Chi) monocytes were not responsible for these effects. The finding that a population of proliferating CD11b+Ly6G− myeloid cells contribute to mechanical inflammatory pain provides a potential cellular target for its treatment in wound inflammation. PMID:26598697

  13. Interactions between CYP11B2 Promoter Methylation and Smoking Increase Risk of Essential Hypertension

    PubMed Central

    Mao, Shuqi; Fan, Rui; Zhong, Fade; Zhu, Fubao; Hao, Lingmei

    2016-01-01

    Aldosterone synthase (CYP11B2) is closely linked to essential hypertension (EH). However, it remains unclear whether the methylation of the CYP11B2 promoter is involved in the development of EH in humans. Our study is aimed at evaluating the contribution of CYP11B2 promoter methylation to the risk of EH. Methylation levels were measured using pyrosequencing technology in 192 participants in a hospital-based case-control study. Logistic regression and multiple linear regression analyses were utilized to adjust for confounding factors and the GMDR method was applied to investigate high-order gene-environment interactions. Although no significant result was observed linking the four analyzed CpG sites to EH, GMDR detected significant interactions among CpG1, CpG3, CpG4, and smoking correlated with an increased risk of EH (OR = 4.62, adjusted P = 0.011). In addition, CpG2 (adjusted P = 0.013) and CpG3 (adjusted P = 0.039) methylation was significantly lower in healthy males than in healthy females. Likewise, after adjusting for confounding factors, CpG2 methylation (adjusted P = 0.007) still showed significant gender-specific differences among the participants of the study. CpG1 (P = 0.009) site was significantly positively correlated with age, and CpG3 (P = 0.007) and CpG4 (P = 0.006) were both inversely linked to smoking. Our findings suggest that gene-environment interactions are associated with the pathogenesis and progression of EH. PMID:28078278

  14. CD11b is protective in complement-mediated immune complex glomerulonephritis

    PubMed Central

    Alexander, Jessy J; Chaves, Lee D; Chang, Anthony; Jacob, Alexander; Ritchie, Maria; Quigg, Richard J

    2015-01-01

    In chronic serum sickness, glomerular immune complexes form, yet C57BL/6 mice do not develop glomerulonephritis unless complement factor H (CfH) is absent, indicating the relevance of complement regulation. Complement receptor 3 (CD11b) and Fcγ receptors on leukocytes, and CfH on platelets, can bind immune complexes. Here we induced immune complex–mediated glomerulonephritis in CfH−/− mice chimeric for wild-type, CfH−/−, CD11b−/−, or FcRγ−/− bone marrow stem cells. Glomerulonephritis was worse in CD11b−/− chimeras compared with all others, whereas disease in FcRγ−/− and wild-type chimeras was comparable. Disease tracked strongly with humoral immune responses, but not glomerular immune complex deposits. Interstitial inflammation with M1 macrophages strongly correlated with glomerulonephritis scores. CD11b−/− chimeras had significantly more M1 macrophages and CD4+ T cells. The renal dendritic cell populations originating from bone marrow–derived CD11c+ cells were similar in all experimental groups. CD11b+ cells bearing colony-stimulating factor 1 receptor were present in kidneys, including CD11b−/− chimeras; these cells correlated negatively with glomerulonephritis scores. Thus, experimental immune complex–mediated glomerulonephritis is associated with accumulation of M1 macrophages and CD4+ T cells in kidneys and functional renal insufficiency. Hence, CD11b on mononuclear cells is instrumental in generating an anti-inflammatory response in the inflamed kidney. PMID:25565310

  15. Two dimensional NMR and NMR relaxation studies of coal structure

    SciTech Connect

    Zilm, K.W.

    1990-01-01

    This report covers the progress made on the title project and summarizes the accomplishments for the project period. Four major areas of inquiry have been pursued. Advanced solid state NMR methods are being developed to assay the distribution of the various important functional groups in coals that determine the reactivity of coals. Other methods are being developed which will also determine how these functional groups are linked together. A third area of investigation concerns how molecular mobility in coals impacts NMR relaxation times, which is important for interpretation of such data in terms of the mobile phase in coals model. Along the same lines the authors are also using these studies to establish protocols for obtaining the best quantitative response from coals in solid state C-13 NMR spectra. The effects of very high MAS rates (>10 kHz) on cross polarization dynamics are also being investigated for similar reasons. The authors have concentrated on a theoretical treatment of pairs of tightly coupled spin {1/2} nuclei under magic angle spinning conditions. The average Hamiltonian theory developed here is required for a quantitative understanding of two dimensional NMR experiments of such spin pairs in solids. These experiments in turn provide a means of determining connectivities between resonances in solid state NMR spectra. Development of these techniques will allow us to establish connectivities between functional components in coals. The complete description of these spin dynamics has turned out to be complex, and is necessary to provide a foundation upon which such experiments may be quantitatively interpreted in complex mixtures such as coals. 25 refs., 4 figs., 3 tabs.

  16. Structure‐function integrity of the adult hippocampus depends on the transcription factor Bcl11b/Ctip2

    PubMed Central

    Simon, R.; Baumann, L.; Fischer, J.; Seigfried, F. A.; De Bruyckere, E.; Liu, P.; Jenkins, N. A.; Copeland, N. G.; Schwegler, H.

    2016-01-01

    The dentate gyrus is one of the only two brain regions where adult neurogenesis occurs. Throughout life, cells of the neuronal stem cell niche undergo proliferation, differentiation and integration into the hippocampal neural circuitry. Ongoing adult neurogenesis is a prerequisite for the maintenance of adult hippocampal functionality. Bcl11b, a zinc finger transcription factor, is expressed by postmitotic granule cells in the developing as well as adult dentate gyrus. We previously showed a critical role of Bcl11b for hippocampal development. Whether Bcl11b is also required for adult hippocampal functions has not been investigated. Using a tetracycline‐dependent inducible mouse model under the control of the forebrain‐specific CaMKIIα promoter, we show here that the adult expression of Bcl11b is essential for survival, differentiation and functional integration of adult‐born granule cell neurons. In addition, Bcl11b is required for survival of pre‐existing mature neurons. Consequently, loss of Bcl11b expression selectively in the adult hippocampus results in impaired spatial working memory. Together, our data uncover for the first time a specific role of Bcl11b in adult hippocampal neurogenesis and function. PMID:26915960

  17. Association between TNFRSF11B gene polymorphisms and history of ischemic stroke in Italian diabetic patients.

    PubMed

    Biscetti, Federico; Straface, Giuseppe; Giovannini, Silvia; Santoliquido, Angelo; Angelini, Flavia; Santoro, Luca; Porreca, Carlo Filippo; Pecorini, Giovanni; Ghirlanda, Giovanni; Flex, Andrea

    2013-01-01

    Osteoprotegerin (OPG) is a secretory glycoprotein that belongs to the tumor necrosis factor receptor family and plays a role in atherosclerosis. The present study aimed to evaluate whether OPG gene (TNFRSF11B) polymorphisms are involved in ischemic stroke in an Italian population with diabetes. Participants in a retrospective case-control study included 364 diabetic patients (180 males, 184 females) with history of ischemic stroke and 492 diabetic subjects without history of ischemic stroke (252 males, 240 females). The T245G, T950C, and G1181C polymorphisms of the OPG gene were analyzed by polymerase chain reaction and restriction fragment length polymorphism. We found that the T245G, T950C, and G1181C gene polymorphisms of the OPG gene were significantly (34.1 vs. 9.5 %, P < 0.0001; 30.8 vs. 6.3 %, P < 0.0001 and 26.4 vs. 11.6 % P < 0.0001, respectively) and independently (adjusted OR 5.15 [3.46-7.68], OR 6.63 [4.26-10.31], and OR 3.03 [2.04-4.50], respectively) associated with history of ischemic stroke. We also found that these three polymorphisms act synergistically in patients with stroke history. The TNFRSF11B gene polymorphisms studied are associated with history of ischemic stroke and synergistic effects between these genotypes might be potential markers for cerebrovascular disorders.

  18. Is lightning a possible source of the radio emission on HAT-P-11b?

    NASA Astrophysics Data System (ADS)

    Hodosán, G.; Rimmer, P. B.; Helling, Ch.

    2016-09-01

    Lightning induced radio emission has been observed on Solar system planets. There have been many attempts to observe exoplanets in the radio wavelength, however, no unequivocal detection has been reported. Lecavelier des Etangs et al. carried out radio transit observations of the exoplanet HAT-P-11b, and suggested that a small part of the radio flux can be attributed to the planet. Here, we assume that this signal is real, and study if this radio emission could be caused by lightning with similar energetic properties like in the Solar system. We find that a lightning storm with 3.8 × 106 times larger flash densities than the Earth-storms with the largest lightning activity is needed to produce the observed signal from HAT-P-11b. The optical emission of such thunderstorm would be comparable to that of the host star. We show that HCN produced by lightning chemistry is observable 2-3 yr after the storm, which produces signatures in the L (3.0-4.0 μm) and N (7.5-14.5 μm) infrared bands. We conclude that it is unlikely that the observed radio signal was produced by lightning, however, future, combined radio and infrared observations may lead to lightning detection on planets outside the Solar system.

  19. The large conductance calcium-activated K(+) channel interacts with the small GTPase Rab11b.

    PubMed

    Sokolowski, Sophia; Harvey, Margaret; Sakai, Yoshihisa; Jordan, Amy; Sokolowski, Bernd

    2012-09-21

    The transduction of sound by the receptor or hair cells of the cochlea leads to the activation of ion channels found in the basal and lateral regions of these cells. Thus, the processing of these transduced signals to the central nervous system is tied to the regulation of baso-lateral ion channels. The large conductance calcium-activated potassium or BK channel was revealed to interact with the small GTPase, Rab11b, which is one of many Rabs found in various endosomal pathways. Immunoelectron microscopy showed the colocalization of these two proteins in receptor cells and auditory neurons. Using Chinese hamster ovary cells as a heterologous expression system, Rab11b increased or decreased BK expression, depending on the overexpression or RNAi knockdown of Rab, respectively. Additional mutation analyses, using a yeast two-hybrid assay, suggested that this GTPase moderately interacts within a region of BK exclusive of the N- or C-terminal tails. These data suggest that this small GTPase regulates BK in a slow recycling process through the endocytic compartment and to the plasmalemma.

  20. Implications of the Secondary Eclipse of Exoplanet HAT-P-11b

    NASA Technical Reports Server (NTRS)

    Barry, Richard K.; Deming, L. D.; Bakos, G.; Harrington, J.; Madhusudhan, N.; Noyes, R.; Seager, S.

    2010-01-01

    We observed exoplanet HAT-P-11b and have successfully detected its secondary eclipse. We conducted observations using the Spitzer Space Telescope in the post-cryo mission at 3.6 microns for a period of 22 hours centered on the anticipated secondary eclipse time, to detect the eclipse and determine its phase. Having detected the secondary eclipse, we are at present making a more focused series of observations in both the 3.6 and 4.5 micron bands to fully characterize it. HAT-P-11b is one of only two known exo-Neptunes and has a period of 4.8878 days, radius of 0.422 RJ, mass of 0.081 MJ and semi-major axis 0.053 AU. Measurements of the secondary eclipse will serve to clarify two key issues; 1) the planetary brightness temperature and the nature of its atmosphere, and 2) the eccentricity of its orbit, with implications for its dynamical evolution. We discuss implications of these observations.

  1. The large conductance calcium-activated K+ channel interacts with the small GTPase Rab11b

    PubMed Central

    Sokolowski, Sophia; Harvey, Margaret; Sakai, Yoshihisa; Jordan, Amy; Sokolowski, Bernd

    2012-01-01

    The transduction of sound by the receptor or hair cells of the cochlea leads to the activation of ion channels found in the basal and lateral regions of these cells. Thus, the processing of these transduced signals to the central nervous system is tied to the regulation of baso-lateral ion channels. The large conductance calcium-activated potassium or BK channel was revealed to interact with the small GTPase, Rab11b, which is one of many Rabs found in various endosomal pathways. Immunoelectron microscopy showed the colocalization of these two proteins in receptor cells and auditory neurons. Using Chinese hamster ovary cells as a heterologous expression system, Rab11b increased or decreased BK expression, depending on the overexpression or RNAi knockdown of Rab, respectively. Additional mutation analyses, using a yeast two-hybrid assay, suggested that this GTPase moderately interacts within a region of BK exclusive of the N- or C-terminal tails. These data suggest that this small GTPase regulates BK in a slow recycling process through the endocytic compartment and to the plasmalemma. PMID:22935415

  2. Folding Model Analysis of Elastic Scattering of 11B from Light, Medium, and Heavy Nuclei

    NASA Astrophysics Data System (ADS)

    Aygun, M.

    2016-11-01

    The elastic scattering angular distributions of 11B projectile on light, medium, and heavy target nuclei including 7Li, 9Be, 12C, 16O, 24,25,26Mg, 27Al, 28Si, 40Ca, 58Ni, 59Co, 60Ni, 197Au, 208Pb, and 209Bi have been analyzed at various incident energies. The theoretical results have been obtained by using two different nuclear potentials within the framework of the optical model (OM). Firstly, the double folding potential for real part and the Wood—Saxon (WS) potential for imaginary part have been applied. Secondly, the calculations with double folding potential for both real and imaginary part have been performed and compared with the experimental data. It has been seen that the results are in very good agreement with the experimental data. Also, the volume integrals and cross-sections for each reaction have been obtained. Finally, a new and simple formula for the imaginary potential depth has been derived to clarify the nuclear interactions of 11B nucleus at low energy reactions.

  3. Measurements of the {sup 25}Mg({sup 11}B,{sup 12}C){sup 24}Na and {sup 25}Mg({sup 11}B,{sup 10}Be){sup 26}Al proton transfer reactions

    SciTech Connect

    Faria, P. N. de; Lichtenthaeler, R.; Guimaraes, V.; Lepine-Szily, A.; Benjamim, E. A.; Lima, G. F.; Moro, A. M.

    2006-08-15

    Angular distributions for the {sup 11}B+{sup 25}Mg elastic scattering, {sup 25}Mg({sup 11}B,{sup 12}C){sup 24}Na proton pickup, and {sup 25}Mg({sup 11}B,{sup 10}Be){sup 26}Al stripping reactions have been measured at E{sub {sup 11}B}=35 MeV. The angular distributions have been analyzed by the distorted-waves Born approximation calculations using the code fresco. The spectroscopic factors for the overlaps <{sup 25}Mg|{sup 26}Al>,<{sup 25}Mg|{sup 24}Na> for the ground state and excited states of {sup 26}Al and {sup 24}Na have been obtained and compared to previous measurements and shell-model calculations.

  4. Two dimensional NMR and NMR relaxation studies of coal structure

    SciTech Connect

    Zilm, K.W.

    1989-01-01

    This report covers the progress made on the title project and summarizes the accomplishments for the project period. Four major areas of inquiry have been pursued. Advanced solid state NMR methods are being developed to assay the distribution of the various important functional groups in coals that determine the reactivity of coals. Other methods are being developed which will also determine how these functional groups are linked together. A third area of investigation concerns how molecular mobility in coals impacts NMR relaxation times, which is important for interpretation of such data in terms of the mobile phase in coal models. Along the same lines the author are also using these studies to establish protocols for obtaining the best quantitative response from coals in solid state C-13 NMR spectra. The effects of very high MAS rates (>10 kHz) on cross polarization dynamics are also being investigated for similar reasons. During the last quarter the authors has concentrated on improvements in cross polarization (CP) sequences with a goal of making the CP process insensitive to experimental conditions such as the Hartmann-Hahn mismatch. It has been found that the usual theories of CP are incorrect, and that the CP process is very heterogeneous in nature. This has significant implications on methods typically used in quantifying {sup 13}C CPMAS spectra of coals. 19 refs., 11 figs.

  5. Infrared and 13C MAS nuclear magnetic resonance spectroscopic study of acetylation of cotton

    NASA Astrophysics Data System (ADS)

    Adebajo, Moses O.; Frost, Ray L.

    2004-01-01

    The acetylation of commercial cotton samples with acetic anhydride without solvents in the presence of about 5% 4-dimethylaminopyridine (DMAP) catalyst was followed using Fourier transform infrared (FTIR) and 13C MAS NMR spectroscopy. This preliminary investigation was conducted in an effort to develop hydrophobic, biodegradable, cellulosic materials for subsequent application in oil spill cleanup. The FTIR results provide clear evidence for successful acetylation though the NMR results indicate that the level of acetylation is low. Nevertheless, the overall results indicate that cotton fibres are potential candidates suitable for further development via acetylation into hydrophobic sorbent materials for subsequent oil spill cleanup application. The results also indicate that de-acetylation, the reverse of the equilibrium acetylation reaction, occurred when the acetylation reaction was prolonged beyond 3 h.

  6. Tissue factor contributes to neutrophil CD11b expression in alpha-naphthylisothiocyanate-treated mice

    SciTech Connect

    Luyendyk, James P.; Flanagan, Kevin C.; Williams, C. David; Jaeschke, Hartmut; Slusser, Joyce G.; Mackman, Nigel

    2011-02-01

    Cholestatic liver injury induced by alpha-naphthylisothiocyanate (ANIT) is provoked by injury to intrahepatic bile ducts and the progression of hepatic necrosis requires the procoagulant protein tissue factor (TF) and extrahepatic cells including neutrophils. Recent studies have shown that myeloid cell TF contributes to neutrophil activation. We tested the hypothesis that myeloid cell TF contributes to neutrophil activation in ANIT-treated mice. TF activity in liver homogenates increased significantly in TF{sup flox/flox} mice treated with ANIT, but not in TF{sup flox/flox}/LysMCre mice (TF{sup {Delta}Myeloid} mice), which have reduced TF expression in monocytes/macrophages and neutrophils. Myeloid cell-specific TF deficiency did not alter expression of the chemokines KC or MIP-2 but reduced hepatic neutrophil accumulation in ANIT-treated mice at 48 h as indicated by tissue myeloperoxidase (MPO) activity. Myeloid cell TF deficiency significantly reduced CD11b expression by blood neutrophils in ANIT-treated mice, and this was associated with reduced plasma MPO protein levels, an index of neutrophil degranulation. However, myeloid cell-specific TF deficiency had no effect on ANIT-induced coagulation cascade activation. The increase in serum ALT and ALP activities in ANIT-treated mice was reduced by myeloid cell TF deficiency (p < 0.05), but the myeloid cell TF deficiency did not reduce hepatic necrosis at 48 h, as determined by histopathology and morphometry. The results suggest that myeloid cell TF contributes to neutrophil CD11b expression during cholestasis by a coagulation-independent pathway. However, the resultant reduction in neutrophil accumulation/activation is insufficient to substantially reduce ANIT hepatotoxicity, suggesting that myeloid cell TF is only one of many factors modulating hepatic necrosis during cholestasis. - Research Highlights: > Myeloid cell tissue factor contributes to liver procoagulant activity during acute cholestasis. > ANIT

  7. High precision 11B/10B analysis with a simplified MC-ICP-MS

    NASA Astrophysics Data System (ADS)

    Tanimizu, M.; Nagaishi, K.

    2012-04-01

    Boron isotope ratio is a powerful tracer in the fields of geochemistry, biochemistry, and environmental chemistry. One important application of 11B/10B isotope ratio in geochemistry is as an indicator for paleo pH of seawater recorded in marine carbonates in deep-sea sediments. Boron isotope ratios are determined by TIMS or MC-ICP-MS with precisions of better than 0.1 % RSD, but a large inter-lab discrepancy of 0.6 % is still observed for actual carbonate samples (Foster, 2008). Here, we tried to determine B isotope ratio by MC-ICP-MS with a simple and common analytical techniques using a quartz sample introduction system with a PFA nebulizer, and compared to recently developed precise B isotope ratio analysis techniques by TIMS in positive ion detection mode determined as Cs2BO2+ ions with sample amount of <100 ng (Ishikawa and Nagaishi, 2011) and by MC-ICP-MS (Foster, 2008, Louvat et al., 2011). 11B/10B isotope ratios of a 50 ppb B solution dissolved in a HNO3, mannitol, HF-mixed solution were determined against an isotopic reference NIST-SRM 951 with a standard sample bracketing technique in the wet plasma condition. Resultant analytical reproducibility (twice standard deviation) was +/-0.02 % with a consumption of 50 ng B, and the washout time was comparable to that of NH3 gas addition to the introduction system (Foster, 2008). 11B/10B isotope ratios of actual carbonate sample and seawater were determined after simple chemical purification with a common cation exchange resin instead of a boron selective resin. Their relative differences from the standard were consistent with those determined by the positive TIMS within analytical uncertainty. Current potential of MC-ICP-MS for precise B isotopic analysis will be discussed. Foster, G., 2008. Seawater pH, pCO2 and [CO32-] variations in the Caribbean Sea over the last 130kyr: A boron isotope and B/Ca study of planktic foraminifera, Earth Planet. Sci. Lett., 271, 254-266. Ishikawa, T. and Nagaishi, K., 2011. High

  8. Cross polarization magic-angle spinning NMR at cryogenic temperatures

    NASA Astrophysics Data System (ADS)

    Macho, V.; Kendrick, R.; Yannoni, C. S.

    A magic angle spinning (MAS) apparatus which can be used for high resolution solid state NMR at temperatures as low as 15 K is described. To demonstrate the utility of this apparatus, 13C spectra of molecules containing methyl groups have been investigated at cryogenic temperatures. The spectra, which are described in detail, provide direct evidence for the slowdown of methyl rotation.

  9. The T-ALL related gene BCL11B regulates the initial stages of human T-cell differentiation.

    PubMed

    Ha, V L; Luong, A; Li, F; Casero, D; Malvar, J; Kim, Y M; Bhatia, R; Crooks, G M; Parekh, C

    2017-03-14

    The initial stages of T-cell differentiation are characterized by a progressive commitment to the T-cell lineage, a process that involves the loss of alternative (myelo-erythroid, NK, B) lineage potentials. Aberrant differentiation during these stages can result in T-cell acute lymphoblastic leukemia (T-ALL). However, the mechanisms regulating the initial stages of human T-cell differentiation are obscure. Through loss of function studies, we showed BCL11B, a transcription factor recurrently mutated T-ALL, is essential for T-lineage commitment, particularly the repression of NK and myeloid potentials, and the induction of T-lineage genes, during the initial stages of human T-cell differentiation. In gain of function studies, BCL11B inhibited growth of and induced a T-lineage transcriptional program in T-ALL cells. We found previously unknown differentiation stage-specific DNA binding of BCL11B at multiple T-lineage genes; target genes showed BCL11B-dependent expression, suggesting a transcriptional activator role for BCL11B at these genes. Transcriptional analyses revealed differences in the regulatory actions of BCL11B between human and murine thymopoiesis. Our studies show BCL11B is a key regulator of the initial stages of human T-cell differentiation and delineate the BCL11B transcriptional program, enabling the dissection of the underpinnings of normal T-cell differentiation and providing a resource for understanding dysregulations in T-ALL.Leukemia advance online publication, 14 March 2017; doi:10.1038/leu.2017.70.

  10. Evolution of magnetic properties and microstructure of Hf2Co11B alloys

    DOE PAGES

    McGuire, Michael A.; Rios, Orlando

    2015-02-05

    Amorphous Hf2Co11B alloys produced by melt-spinning have been crystallized by annealing at 500-800 °C, and the products have been investigated using magnetization measurements, x-ray diffraction, and scanning electron microscopy. The results reveal the evolution of the phase fractions, microstructure, and magnetic properties with both annealing temperature and time. Crystallization of the phase denoted HfCo7, which is associated with the development of coercivity, occurs slowly at 500 °C. Annealing at intermediate temperatures produces mixed phase samples containing some of the HfCo7 phase with the highest values of remanent magnetization and coercivity. The equilibrium structure at 800 °C contains HfCo3B2, Hf6Co23 andmore » Co, and displays soft ferromagnetism. Maximum values for the remanent magnetization, intrinsic coercivity, and magnetic energy product among the samples are approximately 5.2 kG, 2.0 kOe, and 3.1 MGOe, respectively, which indicates that the significantly higher values observed in crystalline, melt-spun Hf2Co11B ribbons are a consequence of the non-equilibrium solidification during the melt-spinning process. Application of high magnetic fields during annealing is observed to strongly affect the microstructural evolution, which may provide access to higher performance materials in Zr/Hf-Co hard ferromagnets. The crystal structure of HfCo7 and the related Zr analogues is unknown, and without knowledge of atomic positions powder diffraction cannot distinguish among proposed unit cells and symmetries found in the literature.« less

  11. Antagonism of CD11b with neutrophil inhibitory factor (NIF) inhibits vascular lesions in diabetic retinopathy.

    PubMed

    Veenstra, Alexander A; Tang, Jie; Kern, Timothy S

    2013-01-01

    Leukocytes and proteins that govern leukocyte adhesion to endothelial cells play a causal role in retinal abnormalities characteristic of the early stages of diabetic retinopathy, including diabetes-induced degeneration of retinal capillaries. Leukocyte integrin αmβ2 (CD11b/CD18, MAC1), a protein mediating adhesion, has been shown to mediate damage to endothelial cells by activated leukocytes in vitro. We hypothesized that Neutrophil Inhibitory Factor (NIF), a selective antagonist of integrin αmβ2, would inhibit the diabetes-induced degeneration of retinal capillaries by inhibiting the excessive interaction between leukocytes and retinal endothelial cells in diabetes. Wild type animals and transgenic animals expressing NIF were made diabetic with streptozotocin and assessed for diabetes-induced retinal vascular abnormalities and leukocyte activation. To assess if the leukocyte blocking therapy compromised the immune system, animals were challenged with bacteria. Retinal superoxide production, leukostasis and leukocyte superoxide production were increased in wild type mice diabetic for 10 weeks, as was the ability of leukocytes isolated from diabetic animals to kill retinal endothelial cells in vitro. Retinal capillary degeneration was significantly increased in wild type mice diabetic 40 weeks. In contrast, mice expressing NIF did not develop any of these abnormalities, with the exception that non-diabetic and diabetic mice expressing NIF generated greater amounts of superoxide than did similar mice not expressing NIF. Importantly, NIF did not significantly impair the ability of mice to clear an opportunistic bacterial challenge, suggesting that NIF did not compromise immune surveillance. We conclude that antagonism of CD11b (integrin αmβ2) by NIF is sufficient to inhibit early stages of diabetic retinopathy, while not compromising the basic immune response.

  12. Evolution of magnetic properties and microstructure of Hf2Co11B alloys

    NASA Astrophysics Data System (ADS)

    McGuire, Michael A.; Rios, Orlando

    2015-02-01

    Amorphous Hf2Co11B alloys produced by melt-spinning have been crystallized by annealing at 500-800 °C, and the products have been investigated using magnetization measurements, x-ray diffraction, and scanning electron microscopy. The results reveal the evolution of the phase fractions, microstructure, and magnetic properties with both annealing temperature and time. Crystallization of the phase denoted HfCo7, which is associated with the development of coercivity, occurs slowly at 500 °C. Annealing at intermediate temperatures produces mixed phase samples containing some of the HfCo7 phase with the highest values of remanent magnetization and coercivity. The equilibrium structure at 800 °C contains HfCo3B2, Hf6Co23, and Co, and displays soft ferromagnetism. Maximum values for the remanent magnetization, intrinsic coercivity, and magnetic energy product among the samples are approximately 5.2 kG, 2.0 kOe, and 3.1 MGOe, respectively, which indicates that the significantly higher values observed in crystalline, melt-spun Hf2Co11B ribbons are a consequence of the non-equilibrium solidification during the melt-spinning process. Application of high magnetic fields during annealing is observed to strongly affect the microstructural evolution, which may provide access to higher performance materials in Zr/Hf-Co hard ferromagnets. The crystal structure of HfCo7 and the related Zr analogues is unknown, and without knowledge of atomic positions powder diffraction cannot distinguish among proposed unit cells and symmetries found in the literature.

  13. Gr-1+CD11b+ cells are responsible for tumor promoting effect of TGF-β in breast cancer progression.

    PubMed

    Li, Zhaoyang; Pang, Yanli; Gara, Sudheer Kumar; Achyut, B R; Heger, Christopher; Goldsmith, Paul K; Lonning, Scott; Yang, Li

    2012-12-01

    One great challenge in our understanding of TGF-β cancer biology and the successful application of TGF-β-targeted therapy is that TGF-β works as both a tumor suppressor and a tumor promoter. The underlying mechanisms for its functional change remain to be elucidated. Using 4T1 mammary tumor model that shares many characteristics with human breast cancer, particularly its ability to spontaneously metastasize to the lungs, we demonstrate that Gr-1+CD11b+ cells or myeloid derived suppressor cells are important mediators in TGF-β regulation of mammary tumor progression. Depletion of Gr-1+CD11b+ cells diminished the antitumor effect of TGF-β neutralization. Two mechanisms were involved: first, treatment with TGF-β neutralization antibody (1D11) significantly decreased the number of Gr-1+CD11b+ cells in tumor tissues and premetastatic lung. This is mediated through increased Gr-1+CD11b+ cell apoptosis. In addition, 1D11 treatment significantly decreased the expression of Th2 cytokines and Arginase 1. Interestingly, the number and property of Gr-1+CD11b+ cells in peripheral blood/draining lymph nodes correlated with tumor size and metastases in response to 1D11 treatment. Our data suggest that the efficacy of TGF-β neutralization depends on the presence of Gr-1+CD11b+ cells, and these cells could be good biomarkers for TGF-β-targeted therapy.

  14. Dynamic nuclear polarization NMR spectroscopy allows high-throughput characterization of microporous organic polymers.

    PubMed

    Blanc, Frédéric; Chong, Samantha Y; McDonald, Tom O; Adams, Dave J; Pawsey, Shane; Caporini, Marc A; Cooper, Andrew I

    2013-10-16

    Dynamic nuclear polarization (DNP) solid-state NMR was used to obtain natural abundance (13)C and (15)N CP MAS NMR spectra of microporous organic polymers with excellent signal-to-noise ratio, allowing for unprecedented details in the molecular structure to be determined for these complex polymer networks. Sensitivity enhancements larger than 10 were obtained with bis-nitroxide radical at 14.1 T and low temperature (∼105 K). This DNP MAS NMR approach allows efficient, high-throughput characterization of libraries of porous polymers prepared by combinatorial chemistry methods.

  15. Studies of minute quantities of natural abundance molecules using 2D heteronuclear correlation spectroscopy under 100kHz MAS

    SciTech Connect

    Nishiyama, Y.; Kobayashi, T.; Malon, M.; Singappuli-Arachchige, D.; Slowing, I. I.; Pruski, M.

    2015-02-16

    Two-dimensional 1H{13C} heteronuclear correlation solid-state NMR spectra of naturally abundant solid materials are presented, acquired using the 0.75-mm magic angle spinning (MAS) probe at spinning rates up to 100 kHz. In spite of the miniscule sample volume (290 nL), high-quality HSQC-type spectra of bulk samples as well as surface-bound molecules can be obtained within hours of experimental time. The experiments are compared with those carried out at 40 kHz MAS using a 1.6-mm probe, which offered higher overall sensitivity due to a larger rotor volume. The benefits of ultrafast MAS in such experiments include superior resolution in 1H dimension without resorting to 1H–1H homonuclear RF decoupling, easy optimization, and applicability to mass-limited samples. As a result, the HMQC spectra of surface-bound species can be also acquired under 100 kHz MAS, although the dephasing of transverse magnetization has significant effect on the efficiency transfer under MAS alone.

  16. Studies of minute quantities of natural abundance molecules using 2D heteronuclear correlation spectroscopy under 100kHz MAS

    DOE PAGES

    Nishiyama, Y.; Kobayashi, T.; Malon, M.; ...

    2015-02-16

    Two-dimensional 1H{13C} heteronuclear correlation solid-state NMR spectra of naturally abundant solid materials are presented, acquired using the 0.75-mm magic angle spinning (MAS) probe at spinning rates up to 100 kHz. In spite of the miniscule sample volume (290 nL), high-quality HSQC-type spectra of bulk samples as well as surface-bound molecules can be obtained within hours of experimental time. The experiments are compared with those carried out at 40 kHz MAS using a 1.6-mm probe, which offered higher overall sensitivity due to a larger rotor volume. The benefits of ultrafast MAS in such experiments include superior resolution in 1H dimensionmore » without resorting to 1H–1H homonuclear RF decoupling, easy optimization, and applicability to mass-limited samples. As a result, the HMQC spectra of surface-bound species can be also acquired under 100 kHz MAS, although the dephasing of transverse magnetization has significant effect on the efficiency transfer under MAS alone.« less

  17. In situ solid-state NMR for heterogeneous catalysis: a joint experimental and theoretical approach.

    PubMed

    Zhang, Weiping; Xu, Shutao; Han, Xiuwen; Bao, Xinhe

    2012-01-07

    In situ solid-state NMR is a well-established tool for investigations of the structures of the adsorbed reactants, intermediates and products on the surface of solid catalysts. The techniques allow identifications of both the active sites such as acidic sites and reaction processes after introduction of adsorbates and reactants inside an NMR rotor under magic angle spinning (MAS). The in situ solid-state NMR studies of the reactions can be achieved in two ways, i.e. under batch-like or continuous-flow conditions. The former technique is low cost and accessible to the commercial instrument while the latter one is close to the real catalytic reactions on the solids. This critical review describes the research progress on the in situ solid-state NMR techniques and the applications in heterogeneous catalysis under batch-like and continuous-flow conditions in recent years. Some typical probe molecules are summarized here to detect the Brønsted and Lewis acidic sites by MAS NMR. The catalytic reactions discussed in this review include methane aromatization, olefin selective oxidation and olefin metathesis on the metal oxide-containing zeolites. With combining the in situ MAS NMR spectroscopy and the density functional theoretical (DFT) calculations, the intermediates on the catalyst can be identified, and the reaction mechanism is revealed. Reaction kinetic analysis in the nanospace instead of in the bulk state can also be performed by employing laser-enhanced MAS NMR techniques in the in situ flow mode (163 references).

  18. Integrin CD11b positively regulates TLR4-induced signalling pathways in dendritic cells but not in macrophages

    NASA Astrophysics Data System (ADS)

    Ling, Guang Sheng; Bennett, Jason; Woollard, Kevin J.; Szajna, Marta; Fossati-Jimack, Liliane; Taylor, Philip R.; Scott, Diane; Franzoso, Guido; Cook, H. Terence; Botto, Marina

    2014-01-01

    Tuned and distinct responses of macrophages and dendritic cells to Toll-like receptor 4 (TLR4) activation induced by lipopolysaccharide (LPS) underpin the balance between innate and adaptive immunity. However, the molecule(s) that confer these cell-type-specific LPS-induced effects remain poorly understood. Here we report that the integrin αM (CD11b) positively regulates LPS-induced signalling pathways selectively in myeloid dendritic cells but not in macrophages. In dendritic cells, which express lower levels of CD14 and TLR4 than macrophages, CD11b promotes MyD88-dependent and MyD88-independent signalling pathways. In particular, in dendritic cells CD11b facilitates LPS-induced TLR4 endocytosis and is required for the subsequent signalling in the endosomes. Consistent with this, CD11b deficiency dampens dendritic cell-mediated TLR4-triggered responses in vivo leading to impaired T-cell activation. Thus, by modulating the trafficking and signalling functions of TLR4 in a cell-type-specific manner CD11b fine tunes the balance between adaptive and innate immune responses initiated by LPS.

  19. Transcription Factor Bcl11b Controls Effector and Memory CD8 T cell Fate Decision and Function during Poxvirus Infection

    PubMed Central

    Abboud, Georges; Stanfield, Jessica; Tahiliani, Vikas; Desai, Pritesh; Hutchinson, Tarun E.; Lorentsen, Kyle J.; Cho, Jonathan J.; Avram, Dorina; Salek-Ardakani, Shahram

    2016-01-01

    CD8+ T cells play an important role in host resistance to many viral infections, but the underlying transcriptional mechanisms governing their differentiation and functionality remain poorly defined. By using a highly virulent systemic and respiratory poxvirus infection in mice, we show that the transcription factor Bcl11b provides a dual trigger that sustains the clonal expansion of virus-specific effector CD8+ T cells, while simultaneously suppressing the expression of surface markers associated with short-lived effector cell (SLEC) differentiation. Additionally, we demonstrate that Bcl11b supports the acquisition of memory precursor effector cell (MPEC) phenotype and, thus, its absence causes near complete loss of lymphoid and lung-resident memory cells. Interestingly, despite having normal levels of T-bet and Eomesodermin, Bcl11b-deficient CD8+ T cells failed to execute effector differentiation needed for anti-viral cytokine production and degranulation, suggesting a non-redundant role of Bcl11b in regulation of this program. Thus, Bcl11b is a critical player in fate decision of SLECs and MPECs, as well as effector function and memory formation. PMID:27790219

  20. On the implementation of a chain nuclear reaction of thermonuclear fusion on the basis of the p+11B process

    NASA Astrophysics Data System (ADS)

    Belyaev, V. S.; Krainov, V. P.; Zagreev, B. V.; Matafonov, A. P.

    2015-07-01

    Various theoretical and experimental schemes for implementing a thermonuclear reactor on the basis of the p+11B reaction are considered. They include beam collisions, fusion in degenerate plasmas, ignition upon plasma acceleration by ponderomotive forces, and the irradiation of a solid-state target from 11B with a proton beam under conditions of a Coulomb explosion of hydrogen microdrops. The possibility of employing ultra-short high-intensity laser pulses to initiate the p+11B reaction under conditions far from thermodynamic equilibrium is discussed. This and some other weakly radioactive thermonuclear reactions are promising owing to their ecological cleanness—there are virtually no neutrons among fusion products. Nuclear reactions that follow the p+11B reaction may generate high-energy protons, sustaining a chain reaction, and this is an advantage of the p+11B option. The approach used also makes it possible to study nuclear reactions under conditions close to those in the early Universe or in the interior of stars.

  1. Ultraviolet Light B-Mediated Inhibition of Skin Catalase Activity Promotes Gr-1+CD11b+ Myeloid Cell Expansion

    PubMed Central

    Sullivan, Nicholas J.; Tober, Kathleen L.; Burns, Erin M.; Schick, Jonathan S.; Riggenbach, Judith A.; Mace, Thomas A.; Bill, Matthew A.; Young, Gregory S.; Oberyszyn, Tatiana M.; Lesinski, Gregory B.

    2011-01-01

    Skin cancer incidence and mortality are higher in men compared to women, but the causes of this sex discrepancy remain largely unknown. Ultraviolet light exposure induces cutaneous inflammation and neutralizes cutaneous antioxidants. Gr-1+CD11b+ myeloid cells are heterogeneous bone marrow-derived cells that promote inflammation-associated carcinogenesis. Reduced activity of catalase, an antioxidant present within skin, has been associated with skin carcinogenesis. We utilized the outbred, immune competent Skh-1 hairless mouse model of ultraviolet light B (UVB)-induced inflammation and non-melanoma skin cancer to further define sex discrepancies in UVB-induced inflammation. Our results demonstrated that male skin had relatively lower baseline catalase activity, which was inhibited following acute UVB exposure in both sexes. Further analysis revealed that skin catalase activity inversely correlated with splenic Gr-1+CD11b+ myeloid cell percentage. Acute UVB exposure induced Gr-1+CD11b+ myeloid cell skin infiltration, which was inhibited to a greater extent in males by topical catalase treatment. In chronic UVB studies, we demonstrated that the percentage of splenic Gr-1+CD11b+ myeloid cells was 55% higher in male tumor-bearing mice compared to their female counterparts. Together, our findings indicate that lower skin catalase activity in male mice may at least in part contribute to increased UVB-induced Gr-1+CD11b+ myeloid cells and subsequent skin carcinogenesis. PMID:22030957

  2. High-Throughput Screening based Identification of Small Molecule Antagonists of Integrin CD11b/CD18 Ligand Binding

    PubMed Central

    Faridi, Mohd Hafeez; Maiguel, Dony; Brown, Brock T.; Suyama, Eigo; Barth, Constantinos J.; Hedrick, Michael; Vasile, Stefan; Sergienko, Eduard; Schürer, Stephan; Gupta, Vineet

    2010-01-01

    Binding of leukocyte specific integrin CD11b/CD18 to its physiologic ligands is important for the development of normal immune response in vivo. Integrin CD11b/CD18 is also a key cellular effector of various inflammatory and autoimmune diseases. However, small molecules selectively inhibiting the function of integrin CD11b/CD18 are currently lacking. We used a newly described cell-based high throughput screening assay to identify a number of highly potent antagonists of integrin CD11b/CD18 from chemical libraries containing >100,000 unique compounds. Computational analyses suggest that the identified compounds cluster into several different chemical classes. A number of the newly identified compounds blocked adhesion of wild-type mouse neutrophils to CD11b/CD18 ligand fibrinogen. Mapping the most active compounds against chemical fingerprints of known antagonists of related integrin CD11a/CD18 shows little structural similarity, suggesting that the newly identified compounds are novel and unique. PMID:20188705

  3. HR-MAS NMR metabolomics of 'Swingle' citrumelo rootstock genetically modified to overproduce proline.

    PubMed

    de Oliveira, Caroline S; Carlos, Eduardo F; Vieira, Luiz G E; Lião, Luciano M; Alcantara, Glaucia B

    2014-08-01

    The accumulation of proline is a typical physiological response to abiotic stresses in higher plants. 'Swingle' citrumelo, an important rootstock for citrus production, has been modified with a mutated Δ(1)-pyrroline-5-carboxylate synthetase gene (VaP5CSF129A) linked to the cauliflower mosaic virus 35S promoter to induce the overproduction of free proline. This paper presents a comparative metabolomic study of nontransgenic versus transgenic 'Swingle' citrumelo plants with high endogenous proline. (1)H high-resolution magic angle spinning nuclear magnetic resonance spectroscopy and multivariate analysis showed significant differences in some metabolites between the nontransgenic and transgenic leaves and roots. The overproduction of proline has reduced the sucrose content in transgenic leaves, revealing a metabolic cost for these plants. In roots, the high level of free proline acts for the adjustment of cation-anion balance, causing the reduction of acetic acid content. The same sucrose level in roots indicates that they can be considered as sucrose sink. Similar behavior may be waited for fruits produced on transgenic rootstock.

  4. Characterization of various magnesium oxides by XRD and {sup 1}H MAS NMR spectroscopy

    SciTech Connect

    Aramendia, M.A.; Benitez, J.A.; Borau, V.; Jimenez, C.; Marinas, J.M.; Ruiz, J.R.; Urbano, F.

    1999-04-01

    A magnesium oxide obtained by thermal decomposition of commercially available magnesium hydroxide was refluxed in water and acetone in order to improve its chemical and textural properties with the purpose of using it as a support for metals in heterogeneous catalysts. X-ray diffraction, CO{sub 2} chemisorption, and {sup 1}H magic-angle spinning nuclear magnetic resonance were used to identify crystal phases, the number of basic sites, and the nature of OH groups in the oxide, respectively.

  5. 13C MAS NMR studies of crystalline cholesterol and lipid mixtures modeling atherosclerotic plaques.

    PubMed Central

    Guo, W; Hamilton, J A

    1996-01-01

    Cholesterol and cholesteryl esters are the predominant lipids of atherosclerotic plaques. To provide fundamental data for the quantitative study of plaque lipids in situ, crystalline cholesterol (CHOL) and CHOL/cholesteryl ester (CE) mixtures with other lipids were studied by solid-state nuclear magnetic resonance with magic-angle-sample spinning. Highly distinctive spectra for three different crystalline structures of CHOL were obtained. When CHOL crystals were mixed with isotropic CE oil, solubilized CHOL (approximately 13 mol % CHOL) was detected by characteristic resonances such as C5, C6, and C3; the excess crystalline CHOL (either anhydrous or monohydrate) remained in its original crystalline structure, without being affected by the coexisting CE. By use of 13C-enriched CHOL, the solubility of CHOL in the CE liquid-crystalline phase (approximately 8 mol %) was measured. When phosphatidylcholine was hydrated in presence of CHOL and CE, magic-angle-sampling nuclear magnetic resonance revealed liquid-crystalline CHOL/phosphatidylcholine multilayers with approximately an equal molar ratio of CHOL/phosphatidylcholine. Excess CHOL existed in the monohydrate crystalline form, and CE in separate oil or crystalline phases, depending on the temperature. The magic-angle-sampling nuclear magnetic resonance protocol for identifying different lipid phases was applied to intact (ex vivo) atherosclerotic plaques of cholesterol-fed rabbits. Liquid, liquid-crystalline, and solid phases of CE were characterized. Images FIGURE 2 PMID:8913623

  6. Friedel's salt formation in sulfoaluminate cements: A combined XRD and {sup 27}Al MAS NMR study

    SciTech Connect

    Paul, G.; Boccaleri, E.; Buzzi, L.; Canonico, F.; Gastaldi, D.

    2015-01-15

    Four different binders based on calcium sulfoaluminate cements have been submitted to accelerated chlorination through ionic exchange on hydrated pastes, in order to investigate their ability to chemically bind chloride ions that might reduce chloride penetration. The composition of hydrated cements before and after the treatment was evaluated by means of an X-Ray Diffraction–{sup 27}Al Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy combined study, allowing to take into account even partially amorphous phases and to make quantitative assumption on the relative abundance of the different aluminium-containing phases. It was found that low SO{sub 3} Sulfoaluminate–Portland ternary systems are the most effective in binding chloride ions and the active role played by different members of the AFm family in chloride uptake was confirmed. Moreover, a peculiar behavior related to the formation of Friedel's salt in different pH conditions was also established for the different cements.

  7. Structural analysis of a signal peptide inside the ribosome tunnel by DNP MAS NMR

    PubMed Central

    Lange, Sascha; Franks, W. Trent; Rajagopalan, Nandhakishore; Döring, Kristina; Geiger, Michel A.; Linden, Arne; van Rossum, Barth-Jan; Kramer, Günter; Bukau, Bernd; Oschkinat, Hartmut

    2016-01-01

    Proteins are synthesized in cells by ribosomes and, in parallel, prepared for folding or targeting. While ribosomal protein synthesis is progressing, the nascent chain exposes amino-terminal signal sequences or transmembrane domains that mediate interactions with specific interaction partners, such as the signal recognition particle (SRP), the SecA–adenosine triphosphatase, or the trigger factor. These binding events can set the course for folding in the cytoplasm and translocation across or insertion into membranes. A distinction of the respective pathways depends largely on the hydrophobicity of the recognition sequence. Hydrophobic transmembrane domains stabilize SRP binding, whereas less hydrophobic signal sequences, typical for periplasmic and outer membrane proteins, stimulate SecA binding and disfavor SRP interactions. In this context, the formation of helical structures of signal peptides within the ribosome was considered to be an important factor. We applied dynamic nuclear polarization magic-angle spinning nuclear magnetic resonance to investigate the conformational states of the disulfide oxidoreductase A (DsbA) signal peptide stalled within the exit tunnel of the ribosome. Our results suggest that the nascent chain comprising the DsbA signal sequence adopts an extended structure in the ribosome with only minor populations of helical structure. PMID:27551685

  8. CMOS analog baseband circuitry for an IEEE 802.11 b/g/n WLAN transceiver

    NASA Astrophysics Data System (ADS)

    Zheng, Gong; Xiaojie, Chu; Qianqian, Lei; Min, Lin; Yin, Shi

    2012-11-01

    An analog baseband circuit for a direct conversion wireless local area network (WLAN) transceiver in a standard 0.13-μm CMOS occupying 1.26 mm2 is presented. The circuit consists of active-RC receiver (RX) 4th order elliptic lowpass filters(LPFs), transmit (PGAs) with DC offset cancellation (DCOC) servo loops, and on-chip output buffers. The RX baseband gain can be programmed in the range of -11 to 49 dB in 2 dB steps with 50-30.2 nV/√Hz input referred noise (IRN) and a 21 to -41 dBm in-band 3rd order interception point (IIP3). The RX/TX LPF cutoff frequencies can be switched between 5 MHz, 10 MHz, and 20 MHz to fulfill the multimode 802.11b/g/n requirements. The TX baseband gain of the I/Q paths are tuned separately from -1.6 to 0.9 dB in 0.1 dB steps to calibrate TX I/Q gain mismatches. By using an identical integrator based elliptic filter synthesis method together with global compensation applied to the LPF capacitor array, the power consumption of the RX LPF is considerably reduced and the proposed chip draws 26.8 mA/8 mA by the RX/TX baseband paths from a 1.2 V supply.

  9. Direct measurement of 11B(p ,γ )12C astrophysical S factors at low energies

    NASA Astrophysics Data System (ADS)

    He, J. J.; Jia, B. L.; Xu, S. W.; Chen, S. Z.; Ma, S. B.; Hou, S. Q.; Hu, J.; Zhang, L. Y.; Yu, X. Q.

    2016-05-01

    We directly measure the absolute cross section of 11B(p ,γ )12C in the energy region of Ec .m .=130 -257 keV by using a thin target for the first time. This work is performed on a 320-kV platform at the Institute of Modern Physics in Lanzhou. The astrophysical S factors of this reaction are obtained for capture to the ground and first excited states of 12C. The properties of the known resonance at ˜150 keV are derived and agree with the previous results. However, in the energy region of 170-240 keV, our S factors are about 15%-50% larger than the adopted values in NACRE II and are also larger than the upper limits of NACRE II by up to ˜20 % . This indicates that our new reaction rate is enhanced by about 15%-50% compared to the NACRE II adopted rate in the temperature region 0.32-0.62 GK.

  10. Multimodal Imaging Using a 11B(d,nγ)12C Source

    NASA Astrophysics Data System (ADS)

    Nattress, Jason; Rose, Paul; Mayer, Michal; Wonders, Marc; Wilhelm, Kyle; Erickson, Anna; Jovanovic, Igor; Multimodal Imaging; Nuclear Detection (MIND) in Active Interrogation Collaboration

    2016-03-01

    Detection of shielded special nuclear material (SNM) still remains one of the greatest challenges facing nuclear security, where small signal-to-background ratios result from complex, challenging configurations of practical objects. Passive detection relies on the spontaneous radioactive decay, whereas active interrogation (AI) uses external probing radiation to identify and characterize the material. AI provides higher signal intensity, providing a more viable method for SNM detection. New and innovative approaches are needed to overcome specific application constraints, such as limited scanning time. We report on a new AI approach that integrates both neutron and gamma transmission signatures to deduce specific material properties that can be utilized to aid SNM identification. The approach uses a single AI source, single detector type imaging system based on the 11B(d,nγ)12C reaction and an array of eight EJ-309 liquid scintillators, respectively. An integral transmission imaging approach has been employed initially for both neutrons and photons, exploiting the detectors' particle discrimination properties. Representative object images using neutrons and photons will be presented.

  11. Complete kinematics measurement of the 11B(p,γ)3α reaction

    NASA Astrophysics Data System (ADS)

    Diget, C. Aa; Fynbo, H. O. U.; Laursen, K. L.; Madsbøl, K. O.; Jørgensen, L.; Kirsebom, O. S.; Riisager, K.

    2012-09-01

    One of the first nuclear reactions measured after the invention of the accelerator by Cockroft and Walton was 11B+p, measured by Rutherford and Oliphant in 1933 [1, 2]. This reaction, however, is not yet fully understood at low incident proton energies [3], and the present paper therefore presents a new measurement with complete-kinematics data utilising modern large-area segmented silicon-strip detectors. The aim of the measurement is twofold: firstly, to fully characterise the triple-α decay of the T=1, 2+ state at 16.11 MeV in 12C; secondly, to search for γ decay of the 2+ state to lower lying states, in particular the newly suggested 2+ state around 9-10 MeV [4]. The isovector M1 population of lower lying 2+ states is strongly favoured over isovector E2 transitions to 0+ states, and the method is therefore a promising method to elucidating this timely question.

  12. THE OBLIQUE ORBIT OF THE SUPER-NEPTUNE HAT-P-11b

    SciTech Connect

    Winn, Joshua N.; Albrecht, Simon; Johnson, John Asher; Howard, Andrew W.; Marcy, Geoffrey W.; Isaacson, Howard; Shporer, Avi; Bakos, Gaspar A.; Hartman, Joel D.

    2010-11-10

    We find the orbit of the Neptune-sized exoplanet HAT-P-11b to be highly inclined relative to the equatorial plane of its host star. This conclusion is based on spectroscopic observations of two transits, which allowed the Rossiter-McLaughlin effect to be detected with an amplitude of 1.5 m s{sup -1}. The sky-projected obliquity is 103{sup +26} {sub -10} deg. This is the smallest exoplanet for which spin-orbit alignment has been measured. The result favors a migration scenario involving few-body interactions followed by tidal dissipation. This finding also conforms with the pattern that the systems with the weakest tidal interactions have the widest spread in obliquities. We predict that the high obliquity of HAT-P-11 will be manifest in transit light curves from the Kepler spacecraft: starspot-crossing anomalies will recur at most once per stellar rotation period, rather than once per orbital period as they would for a well-aligned system.

  13. Natural-abundance solid-state 2H NMR spectroscopy at high magnetic field.

    PubMed

    Aliev, Abil E; Mann, Sam E; Iuga, Dinu; Hughes, Colan E; Harris, Kenneth D M

    2011-06-09

    High-resolution solid-state (2)H NMR spectroscopy provides a method for measuring (1)H NMR chemical shifts in solids and is advantageous over the direct measurement of high-resolution solid-state (1)H NMR spectra, as it requires only the application of routine magic angle sample spinning (MAS) and routine (1)H decoupling methods, in contrast to the requirement for complex pulse sequences for homonuclear (1)H decoupling and ultrafast MAS in the case of high-resolution solid-state (1)H NMR. However, a significant obstacle to the routine application of high-resolution solid-state (2)H NMR is the very low natural abundance of (2)H, with the consequent problem of inherently low sensitivity. Here, we explore the feasibility of measuring (2)H MAS NMR spectra of various solids with natural isotopic abundances at high magnetic field (850 MHz), focusing on samples of amino acids, peptides, collagen, and various organic solids. The results show that high-resolution solid-state (2)H NMR can be used successfully to measure isotropic (1)H chemical shifts in favorable cases, particularly for mobile functional groups, such as methyl and -N(+)H(3) groups, and in some cases phenyl groups. Furthermore, we demonstrate that routine (2)H MAS NMR measurements can be exploited for assessing the relative dynamics of different functional groups in a molecule and for assessing whole-molecule motions in the solid state. The magnitude and field-dependence of second-order shifts due to the (2)H quadrupole interaction are also investigated, on the basis of analysis of simulated and experimental (1)H and (2)H MAS NMR spectra of fully deuterated and selectively deuterated samples of the α polymorph of glycine at two different magnetic field strengths.

  14. {alpha} resonance structure in {sup 11}B studied via resonant scattering of {sup 7}Li+{alpha}

    SciTech Connect

    Yamaguchi, H.; Hashimoto, T.; Hayakawa, S.; Binh, D. N.; Kahl, D.; Kubono, S.; Wakabayashi, Y.; Kawabata, T.; Teranishi, T.

    2011-03-15

    A new measurement of {alpha} resonant scattering on {sup 7}Li was performed over the excitation energy of 10.2-13.0 MeV in {sup 11}B at the low-energy RI beam facility CNS Radioactive Ion Beam separator (CRIB) of the Center for Nuclear Study (CNS), University of Tokyo. The excitation function of {sup 7}Li+{alpha} at 180 deg. in the center-of-mass system was successfully measured for the first time with the inverse kinematics method, providing important information on the {alpha} cluster structure in {sup 11}B and the reaction rate of {sup 7}Li({alpha},{gamma}), which is relevant to the {sup 11}B production in the {nu} process in core-collapse supernovae. The excitation function of the {sup 7}Li({alpha},p) reaction cross section for 11.7-13.1 MeV was also measured.

  15. Mechanism of Solid-State Thermolysis of Ammonia Boraine: 15N NMR Study Using Fast Magic-Angle Spinning and Dynamic Nuclear Polarization

    SciTech Connect

    Kobayashi, Takeshi; Gupta, Shalabh; Caporini, Marc A; Pecharsky, Vitalij K; Pruski, Marek

    2014-08-28

    The solid-state thermolysis of ammonia borane (NH3BH3, AB) was explored using state-of-the-art 15N solid-state NMR spectroscopy, including 2D indirectly detected 1H{15N} heteronuclear correlation and dynamic nuclear polarization (DNP)-enhanced 15N{1H} cross-polarization experiments as well as 11B NMR. The complementary use of 15N and 11B NMR experiments, supported by density functional theory calculations of the chemical shift tensors, provided insights into the dehydrogenation mechanism of AB—insights that have not been available by 11B NMR alone. Specifically, highly branched polyaminoborane derivatives were shown to form from AB via oligomerization in the “head-to-tail” manner, which then transform directly into hexagonal boron nitride analog through the dehydrocyclization reaction, bypassing the formation of polyiminoborane.

  16. Microcoils and microsamples in solid-state NMR.

    PubMed

    Takeda, Kazuyuki

    2012-01-01

    Recent reports on microcoils are reviewed. The first part of the review includes a discussion of how the geometries of the sample and coil affect the NMR signal intensity. In addition to derivation of the well-known result that the signal intensity increases as the coil size decreases, the prediction that dilution of a small sample with magnetically inert matter leads to better sensitivity if a tiny coil is not available is given. The second part of the review focuses on the issues specific to solid-state NMR. They include realization of magic-angle spinning (MAS) using a microcoil and harnessing of such strong pulses that are feasible only with a microcoil. Two strategies for microcoil MAS, the piggyback method and magic-angle coil spinning (MACS), are reviewed. In addition, MAS of flat, disk-shaped samples is discussed in the context of solid-state NMR of small-volume samples. Strong RF irradiation, which has been exploited in wide-line spectral excitation, multiple-quantum MAS (MQMAS), and dipolar decoupling experiments, has been accompanied by new challenges regarding the Bloch-Siegert effect, the minimum time resolution of the spectrometer, and the time scale of pulse transient effects. For a possible solution to the latter problem, recent reports on active compensation of pulse transients are described.

  17. [sup 12]C([gamma],[ital p])[sup 11]B cross section from 80 to 157 MeV

    SciTech Connect

    Harty, P.D.; McGeorge, J.C.; MacGregor, I.J.D.; Owens, R.O.; Annand, J.R.M.; Anthony, I.; Crawford, G.I.; Dancer, S.N.; Hall, S.J.; Kellie, J.D.; Miller, G.J. ); Schoch, B.; Beck, R.; Schmieden, H.; Vogt, J.M. ); Ryckebusch, J. )

    1995-04-01

    The [sup 12]C([gamma],[ital p])[sup 11]B differential cross section has been measured over proton angles ranging from 58[degree] to 128[degree], using tagged photons of energy 80--157 MeV, for low-lying regions of residual excitation energy in [sup 11]B. The data have been compared with four different types of calculation. It is shown that scaling of the cross section with momentum mismatch occurs for both the ground-state and excited-state data.

  18. Analysis of Radiation Induced Degradation in FPC-461 Fluoropolymers by Variable Temperature Multinuclear NMR

    SciTech Connect

    Chinn, S C; Wilson, T S; Maxwell, R S

    2004-10-27

    Solid state nuclear magnetic resonance techniques have been used to investigate aging mechanisms in a vinyl chloride:chlorotrifluoroethylene copolymer, FPC-461, due to exposure to {gamma}-radiation. Solid state {sup 1}H MAS NMR spectra revealed structural changes of the polymer upon irradiation under both air and nitrogen atmospheres. Considerable degradation is seen with {sup 1}H NMR in the vinyl chloride region of the polymer, particularly in the samples irradiated in air. {sup 19}F MAS NMR was used to investigate speciation in the chlorotrifluoroethylene blocks, though negligible changes were seen. {sup 1}H and {sup 19}F NMR at elevated temperature revealed increased segmental mobility and decreased structural heterogeneity within the polymer, yielding significant resolution enhancement over room temperature solid state detection. The effects of multi-site exchange are manifest in both the {sup 1}H and {sup 19}F NMR spectra as a line broadening and change in peak position as a function of temperature.

  19. Rapid Proton-Detected NMR Assignment for Proteins with Fast Magic Angle Spinning

    PubMed Central

    2015-01-01

    Using a set of six 1H-detected triple-resonance NMR experiments, we establish a method for sequence-specific backbone resonance assignment of magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectra of 5–30 kDa proteins. The approach relies on perdeuteration, amide 2H/1H exchange, high magnetic fields, and high-spinning frequencies (ωr/2π ≥ 60 kHz) and yields high-quality NMR data, enabling the use of automated analysis. The method is validated with five examples of proteins in different condensed states, including two microcrystalline proteins, a sedimented virus capsid, and two membrane-embedded systems. In comparison to contemporary 13C/15N-based methods, this approach facilitates and accelerates the MAS NMR assignment process, shortening the spectral acquisition times and enabling the use of unsupervised state-of-the-art computational data analysis protocols originally developed for solution NMR. PMID:25102442

  20. Rapid proton-detected NMR assignment for proteins with fast magic angle spinning.

    PubMed

    Barbet-Massin, Emeline; Pell, Andrew J; Retel, Joren S; Andreas, Loren B; Jaudzems, Kristaps; Franks, W Trent; Nieuwkoop, Andrew J; Hiller, Matthias; Higman, Victoria; Guerry, Paul; Bertarello, Andrea; Knight, Michael J; Felletti, Michele; Le Marchand, Tanguy; Kotelovica, Svetlana; Akopjana, Inara; Tars, Kaspars; Stoppini, Monica; Bellotti, Vittorio; Bolognesi, Martino; Ricagno, Stefano; Chou, James J; Griffin, Robert G; Oschkinat, Hartmut; Lesage, Anne; Emsley, Lyndon; Herrmann, Torsten; Pintacuda, Guido

    2014-09-03

    Using a set of six (1)H-detected triple-resonance NMR experiments, we establish a method for sequence-specific backbone resonance assignment of magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectra of 5-30 kDa proteins. The approach relies on perdeuteration, amide (2)H/(1)H exchange, high magnetic fields, and high-spinning frequencies (ωr/2π ≥ 60 kHz) and yields high-quality NMR data, enabling the use of automated analysis. The method is validated with five examples of proteins in different condensed states, including two microcrystalline proteins, a sedimented virus capsid, and two membrane-embedded systems. In comparison to contemporary (13)C/(15)N-based methods, this approach facilitates and accelerates the MAS NMR assignment process, shortening the spectral acquisition times and enabling the use of unsupervised state-of-the-art computational data analysis protocols originally developed for solution NMR.

  1. Growth Hormone With Aromatase Inhibitor May Improve Height in CYP11B1 Congenital Adrenal Hyperplasia.

    PubMed

    Hawton, Katherine; Walton-Betancourth, Sandra; Rumsby, Gill; Raine, Joseph; Dattani, Mehul

    2017-02-01

    With an estimated prevalence of 1 in 100 000 births, 11β-hydroxylase deficiency is the second most common form of congenital adrenal hyperplasia (CAH) and is caused by mutations in CYP11B1 Clinical features include virilization, early gonadotropin-independent precocious puberty, hypertension, and reduced stature. The current mainstay of management is with glucocorticoids to replace deficient steroids and to minimize adrenal sex hormone overproduction, thus preventing virilization and optimizing growth. We report a patient with CAH who had been suboptimally treated and presented to us at 6 years of age with precocious puberty, hypertension, tall stature, advanced bone age, and a predicted final height of 150 cm. Hormonal profiles and genetic analysis confirmed a diagnosis of 11β-hydroxylase deficiency. In addition to glucocorticoid replacement, the patient was commenced on growth hormone and a third-generation aromatase inhibitor, anastrozole, in an attempt to optimize his growth. After the initiation of this treatment, the patient's growth rate improved significantly and bone age advancement slowed. The patient reached a final height of 177.5 cm (0.81 SD score), 11.5 cm above his mid-parental height. This patient is only the second reported case of the use of an aromatase inhibitor in combination with growth hormone to optimize height in 11β-hydroxylase-deficient CAH. This novel treatment proved to be highly efficacious, with no adverse effects. It may therefore provide a promising option to promote growth in exceptional circumstances in individuals with 11β-hydroxylase deficiency presenting late with advanced skeletal maturation and consequent short stature.

  2. Kepler and Ground-Based Transits of the exo-Neptune HAT-P-11b

    NASA Technical Reports Server (NTRS)

    Deming, Drake; Sada, Pedro V.; Jackson, Brian; Peterson, Steven W.; Agol, Eric; Knutson, Heather A.; Jennings, Donald E.; Haase, Plynn; Bays, Kevin

    2011-01-01

    We analyze 26 archival Kepler transits of the exo-Neptune HAT-P-11b, supplemented by ground-based transits observed in the blue (B band) and near-IR (J band). Both the planet and host star are smaller than previously believed; our analysis yields Rp = 4.31 R xor 0.06 R xor and Rs = 0.683 R solar mass 0.009 R solar mass, both about 3 sigma smaller than the discovery values. Our ground-based transit data at wavelengths bracketing the Kepler bandpass serve to check the wavelength dependence of stellar limb darkening, and the J-band transit provides a precise and independent constraint on the transit duration. Both the limb darkening and transit duration from our ground-based data are consistent with the new Kepler values for the system parameters. Our smaller radius for the planet implies that its gaseous envelope can be less extensive than previously believed, being very similar to the H-He envelope of GJ 436b and Kepler-4b. HAT-P-11 is an active star, and signatures of star spot crossings are ubiquitous in the Kepler transit data. We develop and apply a methodology to correct the planetary radius for the presence of both crossed and uncrossed star spots. Star spot crossings are concentrated at phases 0.002 and +0.006. This is consistent with inferences from Rossiter-McLaughlin measurements that the planet transits nearly perpendicular to the stellar equator. We identify the dominant phases of star spot crossings with active latitudes on the star, and infer that the stellar rotational pole is inclined at about 12 deg 5 deg to the plane of the sky. We point out that precise transit measurements over long durations could in principle allow us to construct a stellar Butterfly diagram to probe the cyclic evolution of magnetic activity on this active K-dwarf star.

  3. EFFECT OF INHALED ENDOTOXIN ON AIRWAY AND CIRCULATING INFLAMMATORY CELL PHAGOCYTOSIS AND CD11B EXPRESSION IN ATOPIC ASTHMATIC SUBJECTS

    EPA Science Inventory

    Effect of inhaled endotoxin on airway and circulating inflammatory cell phagocytosis and CD11b expression in atopic asthmatic subjects

    Neil E. Alexis, PhD, Marlowe W. Eldridge, MD, David B. Peden, MD, MS

    Chapel Hill and Research Triangle Park, NC

    Backgrou...

  4. In vivo transmigrated monocytes from patients with stable coronary artery disease have a reduced expression of CD11b.

    PubMed

    Paulsson, J M; Dadfar, E; Held, C; Jacobson, S H; Lundahl, J

    2008-08-01

    Coronary artery disease (CAD) is characterized by infiltration of monocyte derived cells in the intima of the vessel wall. We hypothesized that accumulation of these cells is caused partly by an altered monocyte transmigration process in CAD. To gain insight into this issue we applied the skin blister method that allows collection of in vivo transmigrated cells at sites of local inflammation. Nineteen patients with stable CAD and 19 matched controls were enrolled. Markers of inflammation and gradients of chemokines, as well as adhesion molecule expression and up-regulation capacity, were studied. The expression of inflammatory markers, such as C-reactive protein, interleukin (IL)-6, tumour necrosis factor-alpha and IL-10, was similar in patients and controls, indicating that patients were in a stable phase of the disease. Expression of adhesion molecules, CD11b and very late activation antigen-4, on peripheral monocytes did not differ between patients and controls. However, following in vivo transmigration, monocytes in patients with CAD had a significantly reduced expression and mobilization of CD11b. The effect on CD11b could not be reproduced by in vitro stimulation with blister fluid, representing a local inflammatory milieu, or in an in vitro system of transmigration. These findings point towards differences in monocyte CD11b expression and availability at an inflammatory site between patients with CAD and healthy controls.

  5. IL-1α induces CD11b(low) alveolar macrophage proliferation and maturation during granuloma formation.

    PubMed

    Huaux, François; Lo Re, Sandra; Giordano, Giulia; Uwambayinema, Francine; Devosse, Raynal; Yakoub, Yousof; Panin, Nadtha; Palmai-Pallag, Mihaly; Rabolli, Virginie; Delos, Monique; Marbaix, Etienne; Dauguet, Nicolas; Couillin, Isabelle; Ryffel, Bernhard; Renauld, Jean-Christophe; Lison, Dominique

    2015-04-01

    Macrophages play a central role in immune and tissue responses of granulomatous lung diseases induced by pathogens and foreign bodies. Circulating monocytes are generally viewed as central precursors of these tissue effector macrophages. Here, we provide evidence that granulomas derive from alveolar macrophages serving as a local reservoir for the expansion of activated phagocytic macrophages. By exploring lung granulomatous responses to silica particles in IL-1-deficient mice, we found that the absence of IL-1α, but not IL-1β, was associated with reduced CD11b(high) phagocytic macrophage accumulation and fewer granulomas. This defect was associated with impaired alveolar clearance and resulted in the development of pulmonary alveolar proteinosis (PAP). Reconstitution of IL-1α(-/-) mice with recombinant IL-1α restored lung clearance functions and the pulmonary accumulation of CD11b(high) phagocytic macrophages. Mechanistically, IL-1α induced the proliferation of CD11b(low) alveolar macrophages and differentiated these cells into CD11b(high) macrophages which perform critical phagocytic functions and organize granuloma. We newly discovered here that IL-1α triggers lung responses requiring macrophage proliferation and maturation from tissue-resident macrophages.

  6. Myeloperoxidase deficiency enhances zymosan phagocytosis associated with up-regulation of surface expression of CD11b in mouse neutrophils.

    PubMed

    Fujimoto, Kenta; Motowaki, Takehiro; Tamura, Naoya; Aratani, Yasuaki

    2016-12-01

    Myeloperoxidase (MPO), a major component of neutrophils, catalyzes the production of hypochlorous acid (HOCl) from hydrogen peroxide and chloride anion. Phagocytosis is a critical event induced by neutrophils for host defense and inflammation. Interestingly, we found that MPO-deficient (MPO(-/-)) neutrophils engulfed larger amounts of zymosan than wild-type neutrophils. Blocking of the CD11b subunit of complement receptor 3 (CR3) as well as inhibition of focal adhesion kinase (FAK) and extracellular signal-regulated kinase (ERK) dramatically reduced zymosan phagocytosis. In contrast, blocking of dectin-1, toll-like receptor 2 (TLR2), or spleen tyrosine kinase (Syk) had no significant effects on phagocytosis. Western blotting analysis showed that inhibition of FAK decreased the phosphorylation of ERK1/2, indicating that ERK1/2 is a downstream regulator of FAK in neutrophils. Importantly, we found that cell surface expression of CD11b and phosphorylation of ERK1/2 was significantly higher in zymosan-stimulated MPO(-/-) neutrophils than in zymosan-stimulated wild-type neutrophils. Pretreatment with the MPO inhibitor 4-aminobenzoic acid hydrazide dramatically enhanced both zymosan phagocytosis and the surface expression of CD11b in wild-type neutrophils, but not in MPO(-/-) neutrophils. Collectively, these results strongly suggest that up-regulation of the CD11b/FAK/ERK signaling pathway due to absence of MPO enhances the zymosan phagocytic activity of mouse neutrophils.

  7. Development of a Physical Employment Testing Battery for Infantry Soldiers: 11B Infantryman and 11C Infantryman - Indirect Fire

    DTIC Science & Technology

    2015-12-01

    USARIEM TECHNICAL REPORT T16-10 DEVELOPMENT OF A PHYSICAL EMPLOYMENT TESTING BATTERY FOR INFANTRY SOLDIERS: 11B INFANTRYMAN AND 11C...62 Study 3: Predictor Test Development .......................................................................... 72 Methods...112 D. Pre- Testing Training Schedule for Potential Study 1 Participants ............. 120 iv E. Minutes of the Infantry Subject Matter

  8. An Analysis of IEEE 802.11B and 802.16 Technologies as Part of the Tactical Internet

    DTIC Science & Technology

    2005-09-01

    MANET, MESH, C2PC, C2CE, 802.16, WIMAX, OFDM , COTS, Common Operational Picture, Common Tactical Picture, WLAN, Bridging, Tactical Internet, PRC- 119...19 a. AN/MRC-142 Digital Wideband Transmission System ( DWTS ...63 B. HARRIS CORPORATION’S IEEE 802.11B BASED SECNET-11 PRODUCTS

  9. Sintering process and critical current density of low activation Mg11B2 superconductors from low temperature to high temperature

    NASA Astrophysics Data System (ADS)

    Cheng, Fang; Liu, Yongchang; Ma, Zongqing; Shahriar Al Hossain, Md; Somer, M.

    2016-08-01

    As the "low activation" superconductor, Mg11B2 has a potential application in superconducting coils for fusion reactor. In present work, the sintering process and critical current density of low activation Mg11B2 superconductors were systemically studied from low temperature to high temperature. It was found that the Jc and Hirr values of Mg11B2 bulks in present work are both obviously higher than that of those samples prepared in previous studies. Furthermore, the low-temperature sintered samples exhibit better Jc performance at high fields than the high-temperature sintered samples, due to strong grain boundaries pinning. On the other hand, the high-temperature sintered samples have higher Jc at low fields compared to low-temperature sintered samples, mainly owing to their better crystallinity and grain connectivity. The highest Jc value (2.20 ×105 A cm-2 at 20 K, self-field) is obtained in the Mg11B2 sample sintered at 850 °C for 45 min.

  10. Formation and decay of {sup 24}Mg in the {sup 13}N+{sup 11}B collision

    SciTech Connect

    Figuera, P.; Amorini, F.; Cabibbo, M.; Papalardo, G.; Rizzo, F.; Tudisco, S.; Bradfield-Smith, W.; Davinson, T.; Di Pietro, A.; Shotter, A. C.; Woods, P. J.; Cardella, G.; Papa, M.; Galster, W.; Leleux, P.; Musumarra, A.; Ninane, A.; Sukosd, C.

    1999-11-16

    Different aspects of the formation and decay of {sup 24}Mg in the collision {sup 13}N+{sup 11}B have been studied using a large solid angle and highly segmented Silicon strip detector. Results concerning the fusion cross section, the 6 {alpha} decay of {sup 24}Mg and the GDR gamma ray emission are discussed.

  11. Formation and Decay of {sup 24}Mg in the {sup 13}N+{sup 11}B Collision

    SciTech Connect

    P. Figuera; F. Amorini; W. Bradfield-Smith; M. Cabibbo; G. Cardella; T. Davinson; A. DiPietro; W. Galster; P. Leleux; A. Musumarra; A. Ninane; M. Papa; G. Pappalardo; F. Rizzo; A.C. Shotter; C. Sukosd; S. Tudisco; P.J. Woods

    1999-12-31

    Different aspects of the formation and decay of {sup 24}Mg in the collision {sup 13}N+{sup 11}B have been studied using a large solid angle and highly segmented Silicon strip detector. Results concerning the fusion cross section, the 6 {alpha} decay of {sup 24}Mg and the GDR gamma ray emission are discussed.

  12. 17 CFR 260.11b-6 - Definition of “self-liquidating paper” in section 311(b)(6).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Rules Under Section 311 § 260.11b-6 Definition of “self-liquidating paper” in section 311(b)(6). The term self-liquidating paper, as used in section 311(b)(6) of the Act, means any draft, bill of exchange, acceptance or obligation which is made, drawn, negotiated or incurred by the obligor for the purpose...

  13. 17 CFR 260.11b-6 - Definition of “self-liquidating paper” in section 311(b)(6).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Rules Under Section 311 § 260.11b-6 Definition of “self-liquidating paper” in section 311(b)(6). The term self-liquidating paper, as used in section 311(b)(6) of the Act, means any draft, bill of exchange, acceptance or obligation which is made, drawn, negotiated or incurred by the obligor for the purpose...

  14. 17 CFR 260.11b-6 - Definition of “self-liquidating paper” in section 311(b)(6).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Rules Under Section 311 § 260.11b-6 Definition of “self-liquidating paper” in section 311(b)(6). The term self-liquidating paper, as used in section 311(b)(6) of the Act, means any draft, bill of exchange, acceptance or obligation which is made, drawn, negotiated or incurred by the obligor for the purpose...

  15. Combined use of 15N and 18O of nitrate and 11B to evaluate nitrate contamination in groundwater

    USGS Publications Warehouse

    Seiler, R.L.

    2005-01-01

    Isotopic composition of NO3 (??15NNO3 and ??18ONO3) and B (??11B) were used to evaluate NO3 contamination and identify geochemical processes occurring in a hydrologically complex Basin and Range valley in northern Nevada with multiple potential sources of NO3. Combined use of these isotopes may be a useful tool in identifying NO3 sources because NO3 and B co-migrate in many environmental settings, their isotopes are fractionated by different environmental processes, and because wastewater and fertilizers may have distinct isotopic signatures for N and B. The principal cause of elevated NO3 concentrations in residential parts of the study area is wastewater and not natural NO3 or fertilizers. This is indicated by some samples with elevated NO3 concentrations plotting along ??15NNO3 and NO3 mixing lines between natural NO3 from the study area and theoretical septic-system effluent. This conclusion is supported by the presence of caffeine in one sample and the absence of samples with elevated NO3 concentrations that fall along mixing lines between natural NO3 and theoretical percolate below fertilized lawns. Nitrogen isotopes alone could not be used to determine NO3 sources in several wells because denitrification blurred the original isotopic signatures. The range of ??11B values in native ground water in the study area (-8.2??? to +21.2???) is large. The samples with the low ??11B values have a geochemical signature characteristic of hydrothermal systems. Physical and chemical data suggest B is not being strongly fractionated by adsorption onto clays. ??11B values from local STP effluent (-2.7???) and wash water from a domestic washing machine (-5.7???) were used to plot mixing lines between wastewater and native ground water. In general, wells with elevated NO3 concentrations fell along mixing lines between wastewater and background water on plots of ??11B against 1/B and Cl/B. Combined use of ??15N and ??11B in the study area was generally successful in

  16. KEPLER AND GROUND-BASED TRANSITS OF THE EXO-NEPTUNE HAT-P-11b

    SciTech Connect

    Deming, Drake; Jackson, Brian; Jennings, Donald E.; Sada, Pedro V.; Peterson, Steven W.; Haase, Flynn; Bays, Kevin; Agol, Eric; Knutson, Heather A.

    2011-10-10

    We analyze 26 archival Kepler transits of the exo-Neptune HAT-P-11b, supplemented by ground-based transits observed in the blue (B band) and near-IR (J band). Both the planet and host star are smaller than previously believed; our analysis yields R{sub p} = 4.31 R{sub +} {+-} 0.06 R{sub +} and R{sub s} = 0.683 R{sub sun} {+-} 0.009 R{sub sun}, both about 3{sigma} smaller than the discovery values. Our ground-based transit data at wavelengths bracketing the Kepler bandpass serve to check the wavelength dependence of stellar limb darkening, and the J-band transit provides a precise and independent constraint on the transit duration. Both the limb darkening and transit duration from our ground-based data are consistent with the new Kepler values for the system parameters. Our smaller radius for the planet implies that its gaseous envelope can be less extensive than previously believed, being very similar to the H-He envelope of GJ 436b and Kepler-4b. HAT-P-11 is an active star, and signatures of star spot crossings are ubiquitous in the Kepler transit data. We develop and apply a methodology to correct the planetary radius for the presence of both crossed and uncrossed star spots. Star spot crossings are concentrated at phases -0.002 and +0.006. This is consistent with inferences from Rossiter-McLaughlin measurements that the planet transits nearly perpendicular to the stellar equator. We identify the dominant phases of star spot crossings with active latitudes on the star, and infer that the stellar rotational pole is inclined at about 12{sup 0} {+-} 5{sup 0} to the plane of the sky. We point out that precise transit measurements over long durations could in principle allow us to construct a stellar Butterfly diagram to probe the cyclic evolution of magnetic activity on this active K-dwarf star.

  17. A reduced population of CD103(+)CD11b(+) dendritic cells has a limited impact on oral Salmonella infection.

    PubMed

    Fernández-Santoscoy, María; Wenzel, Ulf Alexander; Persson, Emma; Yrlid, Ulf; Agace, William; Wick, Mary Jo

    2016-08-01

    CD103(+)CD11b(+) dendritic cells (DC) are the major migratory DC subset in the small intestine lamina propria (siLP) and their survival is dependent on the transcription factor interferon regulatory factor 4 (IRF4). Mice with a DC-specific deletion of irf4 (CD11c-cre.Irf4 mice) have reduced mucosal CD103(+)CD11b(+) DC and altered T cell differentiation to protein antigen. The influence of CD103(+)CD11b(+) DC on oral infection with the gastrointestinal pathogen Salmonella, however, is poorly understood and is investigated here. We show that, despite being infected with Salmonella, CD11c-cre.Irf4 mice (called Cre(+) mice) conserve the reduction in CD103(+)CD11b(+) DC observed in naive Cre(+) mice, particularly in the mesenteric lymph nodes (MLN) but also in the siLP at day 3 post infection. Moreover, Salmonella-infected Cre(+) mice have a similar bacterial burden in intestinal tissues (siLP, MLN and Peyer's patches) as well as the spleen compared to infected Cre(-) controls. The T cell compartment, including the frequency of IFN-γ and IL-17-producing T cells, is not altered in intestinal tissues of Salmonella-infected Cre(+) mice relative to infected Cre(-) controls. In addition, no difference between infected Cre(+) and Cre(-) mice was observed in either the concentration of IL-6 or IL-17 in whole tissue lysates of siLP, MLN or Peyer's patches or in the serum concentration of Salmonella-specific IgG and IgM. Overall the data suggest that the reduction of CD103(+)CD11b(+) DC in Cre(+) mice has little if any impact on Salmonella burden in infected tissues or eliciting effector functions important in host survival at later stages of the infection.

  18. Recruitment of bone marrow CD11b+Gr-1+ cells by polymeric nanoparticles for antigen cross-presentation

    PubMed Central

    Yang, Ya-Wun; Luo, Wen-Hui

    2017-01-01

    The objective of this study was to investigate the function of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) on the activation of antigen-specific CD8+ T cell responses via the CD11b+Gr−1+ myeloid subpopulations in murine bone marrow (BM). PLGA NPs containing ovalbumin (OVA) were fabricated by the double-emulsion method. The CD11b+Gr-1lowLy-6Chigh and CD11b+Gr-1highLy-6Clow subsets from mice bone marrow were sorted and treated with the PLGA/OVA NPs, followed by co-culture with the carboxyfluorescein succinimidyl ester (CFSE)-labelled OT-I CD8+ cells. Co-culture of OT-I CD8+ T cells with PLGA/OVA NPs-primed CD11b+Gr-1+ subsets upregulated the expression of IL-2, TNF-α, INF-γ, granzyme B, and perforin, resulting in proliferation of CD8+ T cells and differentiation into effector cytotoxic T lymphocytes (CTLs). In vivo proliferation of CFSE-labelled OT-I CD8+ cells in response to OVA was also obtained in the animals immunized with PLGA/OVA NPs. The results presented in this study demonstrate the ability of polymeric NPs to recruit two CD11b+Gr−1+ myeloid subsets for effective presentation of exogenous antigen to OT-I CD8+ T cells in the context of major histocompatibility complex (MHC) class I, leading to an induction of antigen-specific cell proliferation and differentiation into effector cells. PMID:28317931

  19. Recruitment of bone marrow CD11b+Gr-1+ cells by polymeric nanoparticles for antigen cross-presentation

    NASA Astrophysics Data System (ADS)

    Yang, Ya-Wun; Luo, Wen-Hui

    2017-03-01

    The objective of this study was to investigate the function of poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) on the activation of antigen-specific CD8+ T cell responses via the CD11b+Gr‑1+ myeloid subpopulations in murine bone marrow (BM). PLGA NPs containing ovalbumin (OVA) were fabricated by the double-emulsion method. The CD11b+Gr-1lowLy-6Chigh and CD11b+Gr-1highLy-6Clow subsets from mice bone marrow were sorted and treated with the PLGA/OVA NPs, followed by co-culture with the carboxyfluorescein succinimidyl ester (CFSE)-labelled OT-I CD8+ cells. Co-culture of OT-I CD8+ T cells with PLGA/OVA NPs-primed CD11b+Gr-1+ subsets upregulated the expression of IL-2, TNF-α, INF-γ, granzyme B, and perforin, resulting in proliferation of CD8+ T cells and differentiation into effector cytotoxic T lymphocytes (CTLs). In vivo proliferation of CFSE-labelled OT-I CD8+ cells in response to OVA was also obtained in the animals immunized with PLGA/OVA NPs. The results presented in this study demonstrate the ability of polymeric NPs to recruit two CD11b+Gr‑1+ myeloid subsets for effective presentation of exogenous antigen to OT-I CD8+ T cells in the context of major histocompatibility complex (MHC) class I, leading to an induction of antigen-specific cell proliferation and differentiation into effector cells.

  20. Biosilica-Entrapped Enzymes Studied by Using Dynamic Nuclear-Polarization-Enhanced High-Field NMR Spectroscopy.

    PubMed

    Ravera, Enrico; Michaelis, Vladimir K; Ong, Ta-Chung; Keeler, Eric G; Martelli, Tommaso; Fragai, Marco; Griffin, Robert G; Luchinat, Claudio

    2015-08-12

    Enzymes are used as environmentally friendly catalysts in many industrial applications, and are frequently immobilized in a matrix to improve their chemical stability for long-term storage and reusability. Recently, it was shown that an atomic-level description of proteins immobilized in a biosilica matrix can be attained by examining their magic-angle spinning (MAS) NMR spectra. However, even though MAS NMR is an excellent tool for determining structure, it is severely hampered by sensitivity. In this work we provide the proof of principle that NMR characterization of biosilica-entrapped enzymes could be assisted by high-field dynamic nuclear polarization (DNP).

  1. NMR analysis of biodiesel

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biodiesel is usually analyzed by the various methods called for in standards such as ASTM D6751 and EN 14214. Nuclear magnetic resonance (NMR) is not one of these methods. However, NMR, with 1H-NMR commonly applied, can be useful in a variety of applications related to biodiesel. These include monit...

  2. Protein structure determination with paramagnetic solid-state NMR spectroscopy.

    PubMed

    Sengupta, Ishita; Nadaud, Philippe S; Jaroniec, Christopher P

    2013-09-17

    Many structures of the proteins and protein assemblies that play central roles in fundamental biological processes and disease pathogenesis are not readily accessible via the conventional techniques of single-crystal X-ray diffraction and solution-state nuclear magnetic resonance (NMR). On the other hand, many of these challenging biological systems are suitable targets for atomic-level structural and dynamic analysis by magic-angle spinning (MAS) solid-state NMR spectroscopy, a technique that has far less stringent limitations on the molecular size and crystalline state. Over the past decade, major advances in instrumentation and methodology have prompted rapid growth in the field of biological solid-state NMR. However, despite this progress, one challenge for the elucidation of three-dimensional (3D) protein structures via conventional MAS NMR methods is the relative lack of long-distance data. Specifically, extracting unambiguous interatomic distance restraints larger than ∼5 Å from through-space magnetic dipole-dipole couplings among the protein (1)H, (13)C, and (15)N nuclei has proven to be a considerable challenge for researchers. It is possible to circumvent this problem by extending the structural studies to include several analogs of the protein of interest, intentionally modified to contain covalently attached paramagnetic tags at selected sites. In these paramagnetic proteins, the hyperfine couplings between the nuclei and unpaired electrons can manifest themselves in NMR spectra in the form of relaxation enhancements of the nuclear spins that depend on the electron-nucleus distance. These effects can be significant for nuclei located up to ∼20 Å away from the paramagnetic center. In this Account, we discuss MAS NMR structural studies of nitroxide and EDTA-Cu(2+) labeled variants of a model 56 amino acid globular protein, B1 immunoglobulin-binding domain of protein G (GB1), in the microcrystalline solid phase. We used a set of six EDTA-Cu(2

  3. Prediction of recrystallization behavior of troglitazone/polyvinylpyrrolidone solid dispersion by solid-state NMR.

    PubMed

    Ito, Atsutoshi; Watanabe, Tomoyuki; Yada, Shuichi; Hamaura, Takeshi; Nakagami, Hiroaki; Higashi, Kenjirou; Moribe, Kunikazu; Yamamoto, Keiji

    2010-01-04

    The purpose of this study was to elaborate the relationship between the (13)C CP/MAS NMR spectra and the recrystallization behavior during the storage of troglitazone solid dispersions. The solid dispersions were prepared by either the solvent method or by co-grinding. The recrystallization behavior under storage conditions at 40 degrees C/94% RH was evaluated by the Kolmogorov-Johnson-Mehl-Avrami (KJMA) equation. Solid dispersions prepared by the solvent method or by prolonged grinding brought about inhibition of the nucleation and the nuclei growth at the same time. No differences in the PXRD profiles were found in the samples prepared by the co-grinding and solvent methods, however, (13)C CP/MAS NMR showed significant differences in the spectra. The correlation coefficients using partial least square regression analysis between the PXRD profiles and the apparent nuclei-growth constant or induction period to nucleation were 0.1305 or 0.6350, respectively. In contrast, those between the (13)C CP/MAS NMR spectra and the constant or the period were 0.9916 or 0.9838, respectively. The (13)C CP/MAS NMR spectra had good correlation with the recrystallization kinetic parameters evaluated by the KJMA equation. Consequently, solid-state NMR was judged to be a useful tool for the prediction of the recrystallization behavior of solid dispersions.

  4. Proton-Detected Solid-State NMR Spectroscopy of Bone with Ultrafast Magic Angle Spinning

    NASA Astrophysics Data System (ADS)

    Mroue, Kamal H.; Nishiyama, Yusuke; Kumar Pandey, Manoj; Gong, Bo; McNerny, Erin; Kohn, David H.; Morris, Michael D.; Ramamoorthy, Ayyalusamy

    2015-07-01

    While obtaining high-resolution structural details from bone is highly important to better understand its mechanical strength and the effects of aging and disease on bone ultrastructure, it has been a major challenge to do so with existing biophysical techniques. Though solid-state NMR spectroscopy has the potential to reveal the structural details of bone, it suffers from poor spectral resolution and sensitivity. Nonetheless, recent developments in magic angle spinning (MAS) NMR technology have made it possible to spin solid samples up to 110 kHz frequency. With such remarkable capabilities, 1H-detected NMR experiments that have traditionally been challenging on rigid solids can now be implemented. Here, we report the first application of multidimensional 1H-detected NMR measurements on bone under ultrafast MAS conditions to provide atomistic-level elucidation of the complex heterogeneous structure of bone. Our investigations demonstrate that two-dimensional 1H/1H chemical shift correlation spectra for bone are obtainable using fp-RFDR (finite-pulse radio-frequency-driven dipolar recoupling) pulse sequence under ultrafast MAS. Our results infer that water exhibits distinct 1H-1H dipolar coupling networks with the backbone and side-chain regions in collagen. These results show the promising potential of proton-detected ultrafast MAS NMR for monitoring structural and dynamic changes caused by mechanical loading and disease in bone.

  5. Infection-induced type I interferons activate CD11b on B-1 cells for subsequent lymph node accumulation

    PubMed Central

    Waffarn, Elizabeth E.; Hastey, Christine J.; Dixit, Neha; Choi, Youn Soo; Cherry, Simon; Kalinke, Ulrich; Simon, Scott I.; Baumgarth, Nicole

    2016-01-01

    Innate-like B-1a lymphocytes rapidly redistribute to regional mediastinal lymph nodes (MedLN) during influenza infection to generate protective IgM. Here we demonstrate that influenza infection-induced type I interferons directly stimulate body cavity B-1 cells and are a necessary signal required for B-1 cell accumulation in MedLN. Vascular mimetic flow chamber studies show that type I interferons increase ligand-mediated B-1 cell adhesion under shear stress by inducing high-affinity conformation shifts of surface-expressed integrins. In vivo trafficking experiments identify CD11b as the non-redundant, interferon-activated integrin required for B-1 cell accumulation in MedLN. Thus CD11b on B-1 cells senses infection-induced innate signals and facilitates their rapid sequester into secondary lymphoid tissues, thereby regulating the accumulation of polyreactive IgM producers at sites of infection. PMID:26612263

  6. Development of a Physical Employment Testing Battery for Infantry Soldiers: 11B Infantryman and 11C Infantryman-Indirect Fire

    DTIC Science & Technology

    2015-12-01

    unique, important in protecting the Soldier, and frequently performed on missions in the field for these MOSs. In addition, the 11B and 11C also...PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER U.S. Army Research Institute of Environmental Medicine I 5...STATEMENT Approved for Public Release; unlimited distribution 13. SUPPLEMENTARY NOTES 14. ABSTRACT The U.S. Army Research Institute of Environmental

  7. Congenital adrenal hyperplasia due to 11-beta-hydroxylase deficiency: functional consequences of four CYP11B1 mutations.

    PubMed

    Menabò, Soara; Polat, Seher; Baldazzi, Lilia; Kulle, Alexandra E; Holterhus, Paul-Martin; Grötzinger, Joachim; Fanelli, Flaminia; Balsamo, Antonio; Riepe, Felix G

    2014-05-01

    Congenital adrenal hyperplasia (CAH) is one of the most common autosomal recessive inherited endocrine disease. Steroid 11β-hydroxylase deficiency (11β-OHD) is the second most common form of CAH. The aim of the study was to study the functional consequences of three novel and one previously described CYP11B1 gene mutations (p.(Arg143Trp), p.(Ala306Val), p.(Glu310Lys) and p.(Arg332Gln)) detected in patients suffering from classical and non-classical 11β-OHD. Functional analyses were performed by using a HEK293 cell in vitro expression system comparing wild type (WT) with mutant 11β-hydroxylase activity. Mutant proteins were examined in silico to study their effect on the three-dimensional structure of the protein. Two mutations (p.(Ala306Val) and p.(Glu310Lys)) detected in patients with classical 11β-OHD showed a nearly complete loss of 11β-hydroxylase activity. The mutations p.(Arg143Trp) and p.(Arg332Gln) detected in patients with non-classical 11β-OHD showed a partial functional impairment with approximately 8% and 6% of WT activity, respectively. Functional mutation analysis allows the classification of novel CYP11B1 mutations as causes of classical and non-classical 11β-OHD. The detection of patients with non-classical phenotypes underscores the importance to screen patients with a phenotype comparable to non-classical 21-hydroxylase deficiency for mutations in the CYP11B1 gene in case of a negative analysis of the CYP21A2 gene. As CYP11B1 mutations are most often individual for a family, the in vitro analysis of novel mutations is essential for clinical and genetic counselling.

  8. Two Novel CYP11B1 Gene Mutations in Patients from Two Croatian Families with 11β-Hydroxylase Deficiency

    PubMed Central

    Dumic, Katja; Yuen, Tony; Grubic, Zorana; Kusec, Vesna; Barisic, Ingeborg; New, Maria I.

    2014-01-01

    Steroid 11β-hydroxylase deficiency (11β-OHD) is the second most common cause of congenital adrenal hyperplasia. Mutations in the CYP11B1 gene, which encodes steroid 11β-hydroxylase, are responsible for this autosomal recessive disorder. Here, we describe the molecular genetics of two previously reported male siblings in whom diagnosis of 11β-OHD has been established based on their hormonal profiles displaying high levels of 11-deoxycortisol and hyperandrogenism. Both patients are compound heterozygous for a novel p.E67fs (c.199delG) mutation in exon 1 and a p.R448H (c.1343G>A) mutation in exon 8. We also report the biochemical and molecular genetics data of one new 11β-OHD patient. Sequencing of the CYP11B1 gene reveals that this patient is compound heterozygous for a novel, previously undescribed p.R141Q (c.422G>A) mutation in exon 3 and a p.T318R (c.953C>G) mutation in exon 5. All three patients are of Croatian (Slavic) origin and there is no self-reported consanguinity in these two families. Results of our investigation confirm that most of the CYP11B1 mutations are private. In order to elucidate the molecular basis for 11β-OHD in the Croatian/Slavic population, it is imperative to perform CYP11B1 genetic analysis in more patients from this region, since so far only four patients from three unrelated Croatian families have been analyzed. PMID:24987415

  9. IFN-γ differentially regulates subsets of Gr-1(+)CD11b(+) myeloid cells in chronic inflammation.

    PubMed

    Zhan, Xiaoxia; Fang, Yimin; Hu, Shengfeng; Wu, Yongjian; Yang, Kun; Liao, Chunxin; Zhang, Yuanqing; Huang, Xi; Wu, Minhao

    2015-08-01

    During chronic inflammation, prolonged over-reactive immune response may lead to tissue destruction, while immune suppression hinders tissue repair and pathogen elimination. Therefore, precise regulation of the immune response is needed to avoid immuno-pathology. Interferon-gamma (IFN-γ) is widely used in clinical treatment of inflammatory diseases. However, the underlying mechanism remains unclear. Here, we evaluated the role of IFN-γ on CD11b(+)Gr-1(+) myeloid cell differentiation and function, using a heat-killed Mycobacterium bovis BCG-induced chronic inflammation model. After challenge with heat-killed BCG, two subpopulations of CD11b(+)Gr-1(+) myeloid cells were generated in the mouse spleen. Phenotypical, morphological and functional analysis indicated that the CD11b(+)Gr-1(high) Ly6G(high) Ly6C(low) subset was neutrophil-like myeloid-derived inducer cells (N-MDICs), which promoted T cell activation, while the other subset was CD11b(+)Gr-1(low) Ly6G(neg) Ly6C(high) monocyte-like myeloid-derived suppressor cells (M-MDSCs) that displayed extensive suppressor function. IFN-γ treatment dampened N-MDICs-mediated T cell activation through up-regulating T cell suppressive mediators, reactive oxygen species (ROS) and arginase I. While for M-MDSCs, IFN-γ reduced their suppressing activity by decreasing the arginase activity. Our study provides evidence that IFN-γ balances the over-reactive vs compromised immune response through different regulation of distinct myeloid subsets, and therefore displays significant therapeutic potential for effective immuno-therapy of chronic inflammatory diseases.

  10. Natural killer cells require monocytic Gr-1(+)/CD11b(+) myeloid cells to eradicate orthotopically engrafted glioma cells.

    PubMed

    Baker, Gregory J; Chockley, Peter; Zamler, Daniel; Castro, Maria G; Lowenstein, Pedro R

    2016-06-01

    Malignant gliomas are resistant to natural killer (NK) cell immune surveillance. However, the mechanisms used by these cancers to suppress antitumor NK cell activity remain poorly understood. We have recently reported on a novel mechanism of innate immune evasion characterized by the overexpression of the carbohydrate-binding protein galectin-1 by both mouse and rat malignant glioma. Here, we investigate the cytokine profile of galectin-1-deficient GL26 cells and describe the process by which these tumors are targeted by the early innate immune system in RAG1(-/-) and C57BL/6J mice. Our data reveal that galectin-1 knockdown in GL26 cells heightens their inflammatory status leading to the rapid recruitment of Gr-1(+)/CD11b(+) myeloid cells and NK1.1(+) NK cells into the brain tumor microenvironment, culminating in tumor clearance. We show that immunodepletion of Gr-1(+) myeloid cells in RAG1(-/-) mice permits the growth of galectin-1-deficient glioma despite the presence of NK cells, thus demonstrating an essential role for myeloid cells in the clearance of galectin-1-deficient glioma. Further characterization of tumor-infiltrating Gr-1(+)/CD11b(+) cells reveals that these cells also express CCR2 and Ly-6C, markers consistent with inflammatory monocytes. Our results demonstrate that Gr-1(+)/CD11b(+) myeloid cells, often referred to as myeloid-derived suppressor cells (MDSCs), are required for antitumor NK cell activity against galectin-1-deficient GL26 glioma. We conclude that glioma-derived galectin-1 represents an important factor in dictating the phenotypic behavior of monocytic Gr-1(+)/CD11b(+) myeloid cells. Galectin-1 suppression may be a valuable treatment approach for clinical glioma by promoting their innate immune-mediated recognition and clearance through the concerted effort of innate myeloid and lymphoid cell lineages.

  11. Coexpression of redox partners increases the hydrocortisone (cortisol) production efficiency in CYP11B1 expressing fission yeast Schizosaccharomyces pombe.

    PubMed

    Hakki, Tarek; Zearo, Silvia; Drăgan, Călin-Aurel; Bureik, Matthias; Bernhardt, Rita

    2008-02-01

    Cytochromes P450 play a vital role in the steroid biosynthesis pathway of the adrenal gland. An example of an essential P450 cytochrome is the steroid 11beta-hydroxylase CYP11B1, which catalyses the conversion of 11-deoxycorticol to hydrocortisone. However, despite its high biotechnological potential, this enzyme has so far been unsuccessfully employed in present-day biotechnology due to a poor expression yield and inherent protein instability. In this study, CYP11B1 was biotransformed into various strains of the yeast Schizosaccharomyces pombe, all of which also expressed the electron transfer proteins adrenodoxin and/or adrenodoxin reductase - central components of the mitochondrial P450 system - in order to maximise hydrocortisone production efficiency in our proposed model system. Site-directed mutagenesis of CYP11B1 at positions 52 and 78 was performed in order to evaluate the impact of altering the amino acids at these sites. It was found that the presence of an isoleucine at position 78 conferred the highest 11beta-hydroxylation activity of CYP11B1. Coexpression of adrenodoxin and adrenodoxin reductase appeared to further increase the 11beta-hydroxylase activity of the enzyme (3.4 fold). Adrenodoxin mutants which were found to significantly enhance enzyme efficiency in other cytochromes in previous studies were also tested in our system. It was found that, in this case, the wild type adrenodoxin was more efficient. The new fission yeast strain TH75 coexpressing the wild type Adx and AdR displays high hydrocortisone production efficiency at an average of 1mM hydrocortisone over a period of 72h, the highest value published to date for this biotransformation. Finally, our research shows that pTH2 is an ideal plasmid for the coexpression of the mitochondrial electron transfer counterparts, adrenodoxin and adrenodoxin reductase, in Schizosaccharomyces pombe, and so could serve as a convenient tool for future biotechnological applications.

  12. Critical role of CD11b+ macrophages and VEGF in inflammatory lymphangiogenesis, antigen clearance, and inflammation resolution.

    PubMed

    Kataru, Raghu P; Jung, Keehoon; Jang, Cholsoon; Yang, Hanseul; Schwendener, Reto A; Baik, Jung Eun; Han, Seung Hyun; Alitalo, Kari; Koh, Gou Young

    2009-05-28

    Using a bacterial pathogen-induced acute inflammation model in the skin, we defined the roles of local lymphatic vessels and draining lymph nodes (DLNs) in antigen clearance and inflammation resolution. At the peak day of inflammation, robust expansion of lymphatic vessels and profound infiltration of CD11b+/Gr-1+ macrophages into the inflamed skin and DLN were observed. Moreover, lymph flow and inflammatory cell migration from the inflamed skin to DLNs were enhanced. Concomitantly, the expression of lymphangiogenic growth factors such as vascular endothelial growth factor C (VEGF-C), VEGF-D, and VEGF-A were significantly up-regulated in the inflamed skin, DLNs, and particularly in enriched CD11b+ macrophages from the DLNs. Depletion of macrophages, or blockade of VEGF-C/D or VEGF-A, largely attenuated these phenomena, and produced notably delayed antigen clearance and inflammation resolution. Conversely, keratin 14 (K14)-VEGF-C transgenic mice, which have dense and enlarged lymphatic vessels in the skin dermis, exhibited accelerated migration of inflammatory cells from the inflamed skin to the DLNs and faster antigen clearance and inflammation resolution. Taken together, these results indicate that VEGF-C, -D, and -A derived from the CD11b+/Gr-1+ macrophages and local inflamed tissues play a critical role in promoting antigen clearance and inflammation resolution.

  13. Use of 87Sr/86Sr and δ11B to Identify Slag-Affected Sediment in Southern Lake Michigan

    USGS Publications Warehouse

    Bayless, E. Randall; Bullen, Thomas D.; Fitzpatrick, John A.

    2004-01-01

    Slag is a ubiquitous byproduct of the iron-smelting industry and influences geochemistry and water quality in adjacent geologic units, ground and surface water. Despite extensive slag deposition along the Indiana shoreline of Lake Michigan, definitive evidence that slag has affected lakebed sediments has not been established. Concerns for the protection of water and ecosystem resources in the Great Lakes motivated this study to determine if strontium and boron isotopes could be used to identify and delineate slag-affected bed sediment in Lake Michigan. Sixty-five samples of bed sediment were acquired from the southern lobe of Lake Michigan and analyzed for 87Sr/86Sr and ??11B. Samples immediately offshore from Indiana steel mills and slag-disposal sites contained higher median 87Sr/86Sr values (0.70881) than shoreline sediments collected elsewhere in the basin (0.70847) and uniquely decreased with increasing distance from the shoreline. The highest ??11B values occurred in sediments from the Indiana shoreline (+12.9 to 16.4???) but were also elevated in sediments collected offshore from three Lake Michigan cities (+11.7 to 12.7???). Contoured isotope data indicated that 82-154 km2 of bed sediment along the Indiana shoreline had elevated 87Sr/86Sr and ??11B values relative to shoreline sediments elsewhere in southern Lake Michigan.

  14. Ornithine decarboxylase, polyamines and CD11b expression in HL-60 cells during differentiation induced by retinoic acid.

    PubMed

    Stabellini, Giordano; Brugnoli, F; Calastrini, C; Vizzotto, L; Vertemati, M; Baroni, T; Caramelli, E; Marinucci, L; Pellati, A; Bertagnolo, V

    2004-01-01

    Polyamines (PA) and retinoic acid affect mammalian cell growth, differentiation and apoptosis. Retinoic acid induces granulocytic differentiation of mieloid cell lines and, during this process, is responsible for the expression of CD11b, a surface antigen. In this study we investigate the effects of retinoic acid on HL-60 cells, monitoring ornithine decarboxylase (ODC) activity (enzyme rate of PA), putrescine (PUT), spermidine (SPD), spermine (SPM) levels, CD11b myeloid surface marker differentiation, cell cycle, and apoptosis. ODC activity and PUT levels are correlated with mieloid cell differentiation induced by retinoic acid treatment. Only the ODC/PUT ratio is connected with retinoic acid treated HL-60 cells. Treated cultures show a decrease of proliferation and a cell block in the G0/G1 phase, with consequent diminished S phase. The G0/G1 and S phases are significantly related to ODC activity and to PUT and SPD behavior, whereas in differentiating condition only the decrease of PUT is related to the S phase. CD11b expression, stimulated by retinoic acid treatment, is associated with the SPM trend. Total PA behavior agrees with apoptotic cell increase after 96 h of stimulation. Our data show that retinoic acid treatment modifies ODC activity and the turnover of PA. PUT, SPD and SPM, therefore, have a different role, and may be involved in the differentiative/apoptotic program of retinoic acid treated HL-60 cells.

  15. Solid State NMR Studies of the Aluminum Hydride Phases

    NASA Technical Reports Server (NTRS)

    Hwang, Son-Jong; Bowman, R. C., Jr.; Graetz, Jason; Reilly, J. J.

    2006-01-01

    Several solid state NMR techniques including magic-angle-spinning (MAS) and multiple-quantum (MQ) MAS experiments have been used to characterize various AlH3 samples. MAS-NMR spectra for the 1H and 27Al nuclei have been obtained on a variety of AlH3 samples that include the (beta)- and (gamma)- phases as well as the most stable (alpha)-phase. While the dominant components in these NMR spectra correspond to the aluminum hydride phases, other species were found that include Al metal, molecular hydrogen (H2), as well as peaks that can be assigned to Al-O species in different configurations. The occurrence and concentration of these extraneous components are dependent upon the initial AlH3 phase composition and preparation procedures. Both the (beta)-AlH3 and (gamma)-AlH3 phases were found to generate substantial amounts of Al metal when the materials were stored at room temperature while the (alpha)-phase materials do not exhibit these changes.

  16. Boron and Strontium isotope systematics in deeply subducted alpine-serpentinites: evidence of high-11B fluid flow

    NASA Astrophysics Data System (ADS)

    Tonarini, Sonia; Scambelluri, Marco

    2010-05-01

    Boron and strontium isotope systematics are widely applied tracers to understand recycling processes during subduction. However, very few studies are addressed to the geochemical behaviour of these isotope ratios in high (HP) to ultrahigh-pressure (UHP) serpentinites that experienced pressure-temperature conditions similar to those of modern subduction zones. Here we present delta-11B and 87Sr/86Sr ratios of the Erro-Tobbio peridotite (Ligurian Alps) a slice of serpentinized mantle involved in subduction and high-pressure recrystallization during the Alpine orogeny. The analyzed sample set includes serpentinized peridotite samples recrystallized at increasing P-T conditions: from relatively low P-T (chrysotile and lizardite are the dominant serpentine minerals) to eclogite-facies conditions (antigorite + olivine + Ti clinohumite form the stable paragenesis). During subduction, ductile deformation under HP conditions was focused in serpentinite mylonite shear zones (high-strain domains) surrounding volumes of HP serpentinized peridotite unaffected by plastic deformation (low-strain domains). The latter diffusely preserve serpentinized mantle peridotites with low P-T overprint retaining pristine mantle textures and assemblages. In general, the delta-11B in these products is heavy, with the majority of samples exceeding delta-11B of 16 permil and reaching extreme values of + 24 permil. The 87Sr/86Sr ratios range between 0.7044 and 0.7065, significantly lower than the values of serpentinites formed during interaction with seawater-dominated fluids and close to the seawater 87Sr/86Sr. In more detail, the low P-T serpentinized peridotites are characterized by the wider range of delta-11B variability (+3.8 to +24 permil). The low-strain HP peridotites show a comparably wide range in delta-11B (+6.8 to +20 permil). More homogeneous and generally higher delta-11B were measured in HP mylonitic serpentinites (delta-11B between +16.7 and +24 permil): these rocks also display

  17. CIRCULATING CD11B EXPRESSION CORRELATES WITH THE NEUTROPHIL RESPONSE AND AIRWAY MCD-14 EXPRESSION IS ENHANCED FOLLOWING OZONE EXPOSURE IN HUMANS

    EPA Science Inventory

    We recently reported that baseline expression of circulating CD11b is associated with the magnitude of the neutrophil response following inhaled endotoxin. In this study, we examined whether circulating CD11b plays a similar role in the inflammatory response following inhaled ozo...

  18. Gr-1+CD11b+ myeloid cells efficiently home to site of injury after intravenous administration and enhance diabetic wound healing by neoangiogenesis.

    PubMed

    Tong, Xiaozhe; Lv, Gang; Huang, Jianhua; Min, Yongfen; Yang, Li; Lin, Pengnian Charles

    2014-06-01

    Vascularization is an important factor that affects diabetic wound healing. There is increasing evidence that myeloid cell lineages play a role in neovascularization. In this study, the efficiency of Gr-1+CD11b+ myeloid cells to home to the site of injury and enhance diabetic wound healing by neoangiogenesis after intravenous administration was investigated. Gr-1+CD11b+ myeloid cells were injected into tail vein after establishment of dorsal window chamber, hindlimb ischaemia and ear-punch injury in diabetic or non-diabetic mice. The Gr-1+CD11b+ myeloid cells efficiently homed to the site of injury after intravenous administration and increased neoangiogenesis. The chemokine receptor type 4 (CXCR4) is robustly expressed by Gr-1+CD11b+ myeloid cells. Inhibition of CXCR4 decreases the homing ability of Gr-1+CD11b+ myeloid cells to the site of injury, which indicates that the CXCR4/SDF-1 axis plays an important role in the homing of Gr-1+CD11b+ myeloid cells to the site of injury. In addition, Gr-1+CD11b+ myeloid cells were found to improve blood flow recovery of ischaemic limb and enhance wound healing in diabetic mice by neoangiogenesis after intravenous administration. Taken together, the results of this study suggest that Gr-1+CD11b+ myeloid cells may serve as a potential cell therapy for diabetic wound healing.

  19. Gr-1intCD11b+ myeloid-derived suppressor cells accumulate in corneal allograft and improve corneal allograft survival.

    PubMed

    Choi, Wungrak; Ji, Yong Woo; Ham, Hwa-Yong; Yeo, Areum; Noh, Hyemi; Jin, Su-Eon; Song, Jong Suk; Kim, Hyeon Chang; Kim, Eung Kwon; Lee, Hyung Keun

    2016-12-01

    We identified the characteristics of myeloid-derived suppressor cells (MDSCs) and investigated their mechanism of induction and their functional role in allograft rejection using a murine corneal allograft model. In mice, MDSCs coexpress CD11b and myeloid differentiation antigen Gr-1. Gr-1(+)CD11b(+) cells infiltrated allografted corneas between 4 d and 4 wk after surgery; however, the frequencies of Gr-1(+)CD11b(+) cells were not different between accepted and rejected allografts or in peripheral blood or BM. Of interest, Gr-1(int)CD11b(+) cells, but not Gr-1(hi)CD11b(+) cells, infiltrated the accepted graft early after surgery and expressed high levels of immunosuppressive cytokines, including IL-10, TGF-β, and TNF-related apoptosis-inducing ligand. This population remained until 4 wk after surgery. In vitro, only high dose (>100 ng/ml) of IFN-γ plus GM-CSF could induce immunosuppressive cytokine expression in Gr-1(int)CD11b(+) cells. Furthermore, adoptive transfer of Gr-1(int)CD11b(+) cells reduced T cell infiltration, which improved graft survival. In conclusion, high-dose IFN-γ in allograft areas is essential for development of Gr-1(int)CD11b(+) MDSCs in corneal allografts, and subtle environmental changes in the early period of the allograft can result in a large difference in graft survival.

  20. Preparation and Evaluation of 99mTc-labeled anti-CD11b Antibody Targeting Inflammatory Microenvironment for Colon Cancer Imaging.

    PubMed

    Cheng, Dengfeng; Zou, Weihong; Li, Xiao; Xiu, Yan; Tan, Hui; Shi, Hongcheng; Yang, Xiangdong

    2015-06-01

    CD11b, an active constituent of innate immune response highly expressed in myeloid-derived suppressor cells (MDSCs), can be used as a marker of inflammatory microenvironment, particularly in tumor tissues. In this research, we aimed to fabricate a (99m)Tc-labeled anti-CD11b antibody as a probe for CD11b(+) myeloid cells in colon cancer imaging with single-photon emission computed tomography (SPECT). In situ murine colon tumor model was established in histidine decarboxylase knockout (Hdc(-/-)) mice by chemicals induction. (99m)Tc-labeled anti-CD11b was obtained with labeling yields of over 30% and radiochemical purity of over 95%. Micro-SPECT/CT scans were performed at 6 h post injection to investigate biodistributions and targeting of the probe. In situ colonic neoplasma as small as 3 mm diameters was clearly identified by imaging; after dissection of the animal, anti-CD11b immunofluorescence staining was performed to identify infiltration of CD11b+ MDSCs in microenvironment of colonic neoplasms. In addition, the images displayed intense signal from bone marrow and spleen, which indicated the origin and migration of CD11b(+) MDSCs in vivo, and these results were further proved by flow cytometry analysis. Therefore, (99m)Tc-labeled anti-CD11b SPECT displayed the potential to facilitate the diagnosis of colon tumor in very early stage via detection of inflammatory microenvironment.

  1. MAS2-8 radar and digital control unit

    NASA Technical Reports Server (NTRS)

    Oberg, J. M.; Ulaby, F. T.

    1974-01-01

    The design of the MAS 2-8 (2 to 8 GHz microwave-active spectrometer), a ground-based sensor system, is presented. A major modification in 1974 to the MAS 2-8, that of a control subsystem to automate the data-taking operation, is the prime focus. The digital control unit automatically changes all system parameters except FM rate and records the return signal on paper tape. The overall system operation and a detailed discussion of the design and operation of the digital control unit are presented.

  2. Electron spin resonance investigations of /sup 11/B/sup 12/C, /sup 11/B/sup 13/C, and /sup 10/B/sup 12/C in neon, argon, and krypton matrices at 4 K: Comparison with theoretical results

    SciTech Connect

    Knight L.B. Jr.; Cobranchi, S.T.; Petty, J.T.; Earl, E.; Feller, D.; Davidson, E.R.

    1989-01-15

    The first spectroscopic study of the diatomic radical BC is reported which confirms previous theoretical predictions of a /sup 4/summation/sup -/ electronic ground state. The nuclear hyperfine interactions (A tensors) obtained for /sup 11/B, /sup 10/B, and /sup 13/C from the electron spin resonance (ESR) measurements are compared with extensive ab initio CI calculations. The BC molecule is one of the first examples of a small high spin radical for such an in-depth experimental--theoretical comparison. The electronic structure of BC obtained from an analysis of the nuclear hyperfine interaction (hfi) is compared to that obtained from a Mulliken-type population analysis conducted on a CI wave function which yields A/sub iso/ and A/sub dip/ results in good agreement with the observed values. The BC radical was generated by the laser vaporization of a boron--carbon mixture and trapped in neon, argon, and krypton matrices at 4 K for a complete ESR characterization. The magnetic parameters (MHz) obtained for /sup 11/B/sup 13/C in solid neon are: g/sub parallel/ = 2.0015(3); g/sub perpendicular/ = 2.0020(3); D(zfs) = 1701(2); /sup 11/B: chemically bondA/sub parallel/chemically bond = 100(1); chemically bondA/sub perpendicular/chemically bond = 79(1); /sup 13/C: chemically bondA/sub parallel/chemically bond = 5(2) and chemically bondA/sub perpendicular/chemically bond = 15(1). Based on comparison with the theoretical results, the most likely choice of signs is that all A values are positive.

  3. Integrated genome-wide genotyping and gene expression profiling reveals BCL11B as a putative oncogene in acute myeloid leukemia with 14q32 aberrations.

    PubMed

    Abbas, Saman; Sanders, Mathijs A; Zeilemaker, Annelieke; Geertsma-Kleinekoort, Wendy M C; Koenders, Jasper E; Kavelaars, Francois G; Abbas, Zabiollah G; Mahamoud, Souad; Chu, Isabel W T; Hoogenboezem, Remco; Peeters, Justine K; van Drunen, Ellen; van Galen, Janneke; Beverloo, H Berna; Löwenberg, Bob; Valk, Peter J M

    2014-05-01

    Acute myeloid leukemia is a neoplasm characterized by recurrent molecular aberrations traditionally demonstrated by cytogenetic analyses. We used high density genome-wide genotyping and gene expression profiling to reveal acquired cryptic abnormalities in acute myeloid leukemia. By genome-wide genotyping of 137 cases of primary acute myeloid leukemia, we disclosed a recurrent focal amplification on chromosome 14q32, which included the genes BCL11B, CCNK, C14orf177 and SETD3, in two cases. In the affected cases, the BCL11B gene showed consistently high mRNA expression, whereas the expression of the other genes was unperturbed. Fluorescence in situ hybridization on 40 cases of acute myeloid leukemia with high BCL11B mRNA expression [2.5-fold above median; 40 out of 530 cases (7.5%)] revealed 14q32 abnormalities in two additional cases. In the four BCL11B-rearranged cases the 14q32 locus was fused to different partner chromosomes. In fact, in two cases, we demonstrated that the focal 14q32 amplifications were integrated into transcriptionally active loci. The translocations involving BCL11B result in increased expression of full-length BCL11B protein. The BCL11B-rearranged acute myeloid leukemias expressed both myeloid and T-cell markers. These biphenotypic acute leukemias all carried FLT3 internal tandem duplications, a characteristic marker of acute myeloid leukemia. BCL11B mRNA expression in acute myeloid leukemia appeared to be strongly associated with expression of other T-cell-specific genes. Myeloid 32D(GCSF-R) cells ectopically expressing Bcl11b showed decreased proliferation rate and less maturation. In conclusion, by an integrated approach involving high-throughput genome-wide genotyping and gene expression profiling we identified BCL11B as a candidate oncogene in acute myeloid leukemia.

  4. Integrated genome-wide genotyping and gene expression profiling reveals BCL11B as a putative oncogene in acute myeloid leukemia with 14q32 aberrations

    PubMed Central

    Abbas, Saman; Sanders, Mathijs A.; Zeilemaker, Annelieke; Geertsma-Kleinekoort, Wendy M.C.; Koenders, Jasper E.; Kavelaars, Francois G.; Abbas, Zabiollah G.; Mahamoud, Souad; Chu, Isabel W.T.; Hoogenboezem, Remco; Peeters, Justine K.; van Drunen, Ellen; van Galen, Janneke; Beverloo, H. Berna; Löwenberg, Bob; Valk, Peter J.M.

    2014-01-01

    Acute myeloid leukemia is a neoplasm characterized by recurrent molecular aberrations traditionally demonstrated by cytogenetic analyses. We used high density genome-wide genotyping and gene expression profiling to reveal acquired cryptic abnormalities in acute myeloid leukemia. By genome-wide genotyping of 137 cases of primary acute myeloid leukemia, we disclosed a recurrent focal amplification on chromosome 14q32, which included the genes BCL11B, CCNK, C14orf177 and SETD3, in two cases. In the affected cases, the BCL11B gene showed consistently high mRNA expression, whereas the expression of the other genes was unperturbed. Fluorescence in situ hybridization on 40 cases of acute myeloid leukemia with high BCL11B mRNA expression [2.5-fold above median; 40 out of 530 cases (7.5%)] revealed 14q32 abnormalities in two additional cases. In the four BCL11B-rearranged cases the 14q32 locus was fused to different partner chromosomes. In fact, in two cases, we demonstrated that the focal 14q32 amplifications were integrated into transcriptionally active loci. The translocations involving BCL11B result in increased expression of full-length BCL11B protein. The BCL11B-rearranged acute myeloid leukemias expressed both myeloid and T-cell markers. These biphenotypic acute leukemias all carried FLT3 internal tandem duplications, a characteristic marker of acute myeloid leukemia. BCL11B mRNA expression in acute myeloid leukemia appeared to be strongly associated with expression of other T-cell-specific genes. Myeloid 32D(GCSF-R) cells ectopically expressing Bcl11b showed decreased proliferation rate and less maturation. In conclusion, by an integrated approach involving high-throughput genome-wide genotyping and gene expression profiling we identified BCL11B as a candidate oncogene in acute myeloid leukemia. PMID:24441149

  5. Tumor-conditioned Gr-1(+)CD11b(+) myeloid cells induce angiogenesis through the synergistic action of CCL2 and CXCL16 in vitro.

    PubMed

    Han, Eun Chun; Lee, Jungwhoi; Ryu, Seung-Wook; Choi, Chulhee

    2014-01-24

    Gr-1(+)CD11b(+) cells can suppress innate and adaptive immunity, and the functional immunosuppressive characteristics of these cells can be modulated by the tumor microenvironment. Since Gr-1(+)CD11(+) cells are also involved in tumor-associated angiogenesis, we hypothesized that the angiogenic nature of Gr-1(+)CD11b(+) cells could be regulated by the tumor milieu. To address this hypothesis, we imitated a tumor microenvironment by exposing Gr-1(+)CD11b(+) cells isolated from spleen of 4T1 mammary carcinoma-bearing mice to tumor-conditioned medium. Supernatants from tumor-conditioned Gr-1(+)CD11b(+) cells significantly induced capillary-like tube formation and migration of human umbilical vein endothelial cells (HUVECs) compared to naive Gr-1(+)CD11b(+) cells. Incubation of Gr-1(+)CD11b(+) cells with tumor-conditioned medium induced production of pro-angiogenic chemokines CCL2 and CXCL16. Pretreatment with an anti-CCL2 antibody, but not an anti-CXCL16 antibody, suppressed the angiogenic effects of tumor-conditioned Gr-1(+)CD11b(+) cells on HUVECs. Simultaneous neutralization of CCL2 and CXCL16 significantly inhibited tube formation and migration of HUVECs compared to the sole neutralization against CCL2. Supernatants from tumor-conditioned Gr-1(+)CD11b(+) cells induced phosphorylation of ERK1/2 in HUVECs, and inhibition of the ERK pathway blocked angiogenic effects. ERK pathway activity was partially abrogated by neutralization of CCL2 and more suppressed by simultaneous neutralization of CCL2 and CXCL16. These results collectively indicate that CCL2 and CXCL16 chemokines produced by tumor-conditioned Gr-1(+)CD11b(+) myeloid cells synergistically induce angiogenesis in vitro by stimulating the ERK1/2 signaling pathway. Thus, regulation of Gr-1(+)CD11b(+) cells in the tumor microenvironment may contribute to angiogenesis through the secretion of pro-angiogenic chemokines.

  6. Sodium ion effect on silk fibroin conformation characterized by solid-state NMR and generalized 2D NMR NMR correlation

    NASA Astrophysics Data System (ADS)

    Ruan, Qing-Xia; Zhou, Ping

    2008-07-01

    In the present work, we investigated Na + ion effect on the silk fibroin (SF) conformation. Samples are Na +-involved regenerated silk fibroin films. 13C CP-MAS NMR demonstrates that as added [Na +] increases, partial silk fibroin conformation transit from helix-form to β-form at certain Na + ion concentration which is much higher than that in Bombyx mori silkworm gland. The generalized two-dimensional NMR-NMR correlation analysis reveals that silk fibroin undergoes several intermediate states during its conformation transition process as [Na +] increase. The appearance order of the intermediates is followed as: helix and/or random coil → helix-like → β-sheet-like → β-sheet, which is the same as that produced by pH decrease from 6.8 to 4.8 in the resultant regenerated silk fibroin films. The binding sites of Na + to silk fibroin might involve the carbonyl oxygen atom of certain amino acids sequence which could promote the formation of β-sheet conformation. Since the Na +sbnd O bond is weak, the ability of Na + inducing the secondary structure transition is weaker than those of Ca 2+, Cu 2+ and even K +. It is maybe a reason why the sodium content is much lower than potassium in the silkworm gland.

  7. Lipopolysaccharide enhances FcγR-dependent functions in vivo through CD11b/CD18 up-regulation

    PubMed Central

    Rubel, C; Miliani De Marval, P; Vermeulen, M; Isturiz, M A; Palermo, M S

    1999-01-01

    Fc receptors for immunoglobulin G (IgG) (FcγR) mediate several defence mechanisms in the course of inflammatory and infectious diseases. In Gram-negative infections, cellular wall lipopolysaccharides (LPS) modulate different immune responses. We have recently demonstrated that murine LPS in vivo treatment significantly increases FcγR-dependent clearance of immune complexes (IC). In addition, we and others have reported the induction of adhesion molecules on macrophages and neutrophils by LPS in vivo and by tumour necrosis factor-α (TNF-α) in vitro. The aim of this paper was to investigate CD11b/CD18 participation in LPS enhancing effects on Fcγ-dependent functionality of tissue macrophages. Our results have demonstrated that LPS can enhance antibody-dependent cellular cytotoxicity (ADCC) and IC-triggered cytotoxicity (IC-Ctx), two reactions which involve the Fcγ-receptor but different lytic mechanisms. In vitro incubation of splenocytes from LPS-treated mice with anti-CD11b/CD18 abrogated ADCC and IC-Ctx enhancement, without affecting FcγR expression. Similar results were obtained with physiological concentrations of fibrinogen. In this way cytotoxic values of LPS-splenocytes decreased to the basal levels of control mice. Time and temperature requirements for such inhibition strongly suggested that anti-CD11b/CD18 could modulate intracellular signals leading to downregulation of FcγR functionality. Data presented herein support the hypothesis that functional and/or physical associations between integrins and FcγR could be critical for the modulation of effector functions during an inflammatory response. PMID:10447764

  8. Trafficking CD11b-positive blood cells deliver therapeutic genes to the brain of amyloid depositing transgenic mice

    PubMed Central

    Lebson, Lori; Nash, Kevin; Kamath, Siddharth; Herber, Donna; Carty, Nikisha; Lee, Daniel; Li, Qingyou; Szekeres, Karoly; Jinwal, Umesh; Koren, John; Dickey, Chad A.; Gottschall, Paul; Morgan, Dave; Gordon, Marcia N

    2010-01-01

    A major question for gene therapy in brain concerns methods to administer therapeutic genes in a uniform manner over major portions of the brain. A second question in neuroimmunology concerns the extent to which monocytes migrate to the CNS in degenerative disorders. Here we show that CD11b+ cells (largely monocytes) isolated from the bone marrow of green fluorescent protein (GFP) expressing donors spontaneously home to compacted amyloid plaques in the brain. Injections of these cells as a single pulse show a rapid clearance from circulation (90 minute half-life) and tissue residence half-lives of roughly 3 days. The uptake into brain was minimal in nontransgenic mice. In transgenic mice containing amyloid deposits, uptake was dramatically increased and associated with a corresponding decrease in monocyte uptake into peripheral organs compared to nontransgenic littermates. Twice weekly infusions of the CD11b+ bone marrow cells transfected with a genetically engineered form of the protease neprilysin completely arrest amyloid deposition in an aggressively depositing transgenic model. Exploiting the natural homing properties of peripherally derived blood cells to deliver therapeutic genes has the advantages of access to the entire CNS, expression largely restricted to sites of injury, low risk of immune reactivity, and fading of expression if adverse reactions are encountered. These observations support the feasibility of testing autologous monocytes for application of therapeutic genes in human CNS disease. Moreover, these data support the results from bone marrow grafts that circulating CD11b+ cells can enter the CNS without requiring the use of lethal irradiation. PMID:20660248

  9. Early infiltration of p40IL12+CCR7+CD11b+ cells is critical for fibrosis development

    PubMed Central

    Correa‐Costa, Matheus; Azevedo, Hatylas; Silva, Reinaldo Correia; Cruz, Mario Costa; Almeida, Maira Estanislau Soares; Hiyane, Meire Ioshie; Moreira‐Filho, Carlos Alberto; Santos, Marinilce Fagundes; Perez, Katia Regina; Cuccovia, Iolanda Midea; Camara, Niels Olsen Saraiva

    2016-01-01

    Abstract Introduction Macrophages are heterogeneous and thus can be correlated with distinct tissue outcomes after injury. Conflicting data have indicated that the M2‐related phenotype directly triggers fibrosis. Conversely, we hypothesize here that the inflammatory milieu provided by early infiltration of pro‐inflammatory macrophages dictates tissue scarring after injury. Methods and Results We first determined that tissue‐localized macrophages exhibit a pro‐inflammatory phenotype (p40IL12+CCR7+CD11b+) during the early phase of a chronic injury model, in contrast to a pro‐resolving phenotype (Arg1+IL10+CD206+CD11b+) at a later stage. Then, we evaluated the effects of injecting macrophages differentiated in vitro in the presence of IFNγ + LPS or IL4 + IL13 or non‐differentiated macrophages (hereafter, M0) on promoting inflammation and progression of chronic injury in macrophage‐depleted mice. In addition to enhancing the expression of pro‐inflammatory cytokines, the injection of M (IFNγ + LPS), but not M (IL4 + IL13) or M0, accentuated fibrosis while augmenting levels of anti‐inflammatory molecules, increasing collagen deposition and impairing organ function. We observed a similar profile after injection of sorted CCR7+CD11b+ cells and a more pronounced effect of M (IFNγ + LPS) cells originated from Stat6−/− mice. The injection of M (IFNγ + LPS) cells was associated with the up‐regulation of inflammation‐ and fibrosis‐related proteins (Thbs1, Mmp7, Mmp8, and Mmp13). Conclusions Our results suggest that pro‐inflammatory macrophages promote microenvironmental changes that may lead to fibrogenesis by inducing an inflammatory milieu that alters a network of extracellular‐related genes, culminating in tissue fibrosis. PMID:27621813

  10. Resolution and polarization distribution in cryogenic DNP/MAS experiments

    PubMed Central

    Barnes, Alexander B.; Corzilius, Björn; Mak-Jurkauskas, Melody L.; Andreas, Loren B.; Bajaj, Vikram S.; Matsuki, Yoh; Belenky, Marina L.; Lugtenburg, Johan; Sirigiri, Jagadishwar R.; Temkin, Richard J.; Herzfeld, Judith; Griffin, Robert G.

    2014-01-01

    This contribution addresses four potential misconceptions associated with high-resolution dynamic nuclear polarization/magic angle spinning (DNP/MAS) experiments. First, spectral resolution is not generally compromised at the cryogenic temperatures at which DNP experiments are performed. As we demonstrate at a modest field of 9 T (380 MHz 1H), 1 ppm linewidths are observed in DNP/MAS spectra of a membrane protein in its native lipid bilayer, and <0.4 ppm linewidths are reported in a crystalline peptide at 85 K. Second, we address the concerns about paramagnetic broadening in DNP/MAS spectra of proteins by demonstrating that the exogenous radical polarizing agents utilized for DNP are distributed in the sample in such a manner as to avoid paramagnetic broadening and thus maintain full spectral resolution. Third, the enhanced polarization is not localized around the polarizing agent, but rather is effectively and uniformly dispersed throughout the sample, even in the case of membrane proteins. Fourth, the distribution of polarization from the electron spins mediated via spin diffusion between 1H–1H strongly dipolar coupled spins is so rapid that shorter magnetization recovery periods between signal averaging transients can be utilized in DNP/MAS experiments than in typical experiments performed at ambient temperature. PMID:20454732

  11. ADP-MAS: A Math and Science Curriculum.

    ERIC Educational Resources Information Center

    National Council of La Raza, Washington, DC.

    This curriculum, Academia del Pueblo-Math and Science (ADP-MAS), is an outgrowth of the National Council of La Raza's Project EXCEL, a supplemental educational enrichment model for at-risk Latino students to be operated by Latino community-based organizations or public institutions, including schools with substantial Latino populations. ADP-MAS…

  12. Simulations of chemical exchange lineshapes in CP/MAS spectra using floquet theory and sparse matrix methods

    PubMed

    Hazendonk; Bain; Grondey; Harrison; Dumont

    2000-09-01

    This paper presents a general method for simulating the effect of chemical exchange on MAS NMR spectra of solid samples. The complication in MAS spectra is that the Hamiltonian itself is time-dependent, due to the spinning of the sample. The approach taken in this work is to use Floquet theory to convert the problem into a time-independent form, and then use established methods (used in liquid NMR simulations) to calculate the lineshape. Floquet theory has been admired for its elegance, but criticized for its computational inefficiencies. This is because it removes the time dependence of the system by expanding the problem in a Fourier-like series. This makes a relatively small, time-dependent calculation into a much larger time-independent one. Typically, we use twice as many Floquet blocks as there are spinning sidebands, so the increase in size is substantial. The problem that this creates stems from the fact that the usual Householder methods for diagonalizing a matrix scale as the cube of the size of the matrix. This would make a Floquet calculation prohibitively long. However, the Floquet matrix is inherently sparse, so sparse matrix methods can produce substantial computational savings. Also, fully diagonalizing a matrix is expensive, but converting the matrix to a tridiagonal form (using iterative Lanczos methods) is much cheaper. The use of the Lanczos methods makes the Floquet calculations feasible as a general method for systems of more than one spin. We show how to set up the full matrix describing chemical exchange in a spinning sample, but the details of how the Lanczos methods work are not included-they are described elsewhere. We then validate the theory by simulating the MAS spectra of dimethyl sulfone both with natural abundance (13)C and with methyl groups labeled with (13)C. The latter system has both dipolar and chemical shielding anisotropy terms contributing to the spectrum. Copyright 2000 Academic Press.

  13. [Hepatic manifestation of a macrophage activation syndrome (MAS)].

    PubMed

    Nagel, Michael; Schwarting, Andreas; Straub, Beate K; Galle, Peter R; Zimmermann, Tim

    2017-04-04

    Background Elevated liver values are the most common pathological laboratory result in Germany. Frequent findings, especially in younger patients, are nutritive- or medicamentous- toxic reasons, viral or autoimmune hepatitis. A macrophage activation syndrome (MAS) may manifest like a viral infectious disease with fever, hepatosplenomegaly and pancytopenia and is associated with a high mortality. It is based on an enhanced activation of macrophages with increased cytokine release, leading to organ damage and multi-organ failure. In addition to genetic causes, MAS is commonly associated with infections and rheumatic diseases. We report the case of a 26-year-old female patient suffering from MAS as a rare cause of elevated liver enzymes. Methods Patient characteristics, laboratory values, liver histology, bone marrow and radiological imaging were documented and analyzed. Case Report After an ordinary upper airway infection with bronchitis, a rheumatic arthritis appeared and was treated with leflunomide und methotrexate. In the further course of the disease, the patient developed an acute hepatitis with fever, pancytopenia and massive hyperferritinemia. Immunohistochemistry of the liver biopsy revealed hemophagocytosis and activation of CD68-positive macrophages. In the radiological and histological diagnostics of the liver and bone marrow, an MAS was diagnosed as underlying disease of the acute hepatitis. Under therapy with prednisolone, the fever disappeared and transaminases and ferritin rapidly normalized. Conclusion Aside from the frequent causes of elevated liver values in younger patients, such as nutritive toxic, drug induced liver injury, viral or autoimmune hepatitis, especially in case of massive hyperferritinemia, a MAS should be considered as a rare cause of acute liver disease.

  14. A very sensitive high-resolution NMR method for quadrupolar nuclei: SPAM-DQF-STMAS.

    PubMed

    Amoureux, Jean-Paul; Flambard, Alexandrine; Delevoye, Laurent; Montagne, Lionel

    2005-07-21

    We show that by combining the intrinsically larger (with respect to MQMAS) efficiency of Double-Quantum Filtered Satellite-Transition MAS (DQF-STMAS), with the large S/N gain of the Soft-Pulse Added Mixing (SPAM) concept, a new very sensitive high-resolution solid-state NMR method can be obtained for semi-integer quadrupolar nuclei.

  15. Rotary echo nutation NMR

    NASA Astrophysics Data System (ADS)

    Janssen, R.; Tijink, G. A. H.; Veeman, W. S.

    1988-01-01

    A two-dimensional solid state NMR experiment which combines rotary echoes and nutation NMR is investigated and used to study different sodium sites in zeolite NaA. It is shown that with this technique sodium ions with different relaxation rates in the rotating frame can be distinguished.

  16. Lectures on pulsed NMR

    SciTech Connect

    Pines, A.

    1988-08-01

    These lectures discuss some recent developments in pulsed NMR, emphasizing fundamental principles with selected illustrative applications. Major topics covered include multiple-quantum spectroscopy, spin decoupling, the interaction of spins with a quantized field, adiabatic rapid passage, spin temperature and statistics of cross-polarization, coherent averaging, and zero field NMR. 32 refs., 56 figs.

  17. Lectures on pulsed NMR

    SciTech Connect

    Pines, A.

    1986-09-01

    These lectures discuss some recent developments in pulsed NMR, emphasizing fundamental principles with selected illustrative applications. Major topics covered include multiple-quantum spectroscopy, spin decoupling, the interaction of spins with a quantized field, adiabatic rapid passage, spin temperature and statistics of cross-polarization, coherent averaging, and zero field NMR. 55 figs.

  18. Transcriptional reprogramming of CD11b+Esam(hi) dendritic cell identity and function by loss of Runx3.

    PubMed

    Dicken, Joseph; Mildner, Alexander; Leshkowitz, Dena; Touw, Ivo P; Hantisteanu, Shay; Jung, Steffen; Groner, Yoram

    2013-01-01

    Classical dendritic cells (cDC) are specialized antigen-presenting cells mediating immunity and tolerance. cDC cell-lineage decisions are largely controlled by transcriptional factor regulatory cascades. Using an in vivo cell-specific targeting of Runx3 at various stages of DC lineage development we show that Runx3 is required for cell-identity, homeostasis and function of splenic Esam(hi) DC. Ablation of Runx3 in DC progenitors led to a substantial decrease in splenic CD4(+)/CD11b(+) DC. Combined chromatin immunoprecipitation sequencing and gene expression analysis of purified DC-subsets revealed that Runx3 is a key gene expression regulator that facilitates specification and homeostasis of CD11b(+)Esam(hi) DC. Mechanistically, loss of Runx3 alters Esam(hi) DC gene expression to a signature characteristic of WT Esam(low) DC. This transcriptional reprogramming caused a cellular change that diminished phagocytosis and hampered Runx3(-/-) Esam(hi) DC capacity to prime CD4(+) T cells, attesting to the significant role of Runx3 in specifying Esam(hi) DC identity and function.

  19. Epigenetic regulation of the placental HSD11B2 barrier and its role as a critical regulator of fetal development.

    PubMed

    Togher, Katie L; Togher, Katie L; O'Keeffe, Majella M; O'Keeffe, Majella M; Khashan, Ali S; Khashan, Ali S; Gutierrez, Humberto; Gutierrez, Humberto; Kenny, Louise C; Kenny, Louise C; O'Keeffe, Gerard W; O'Keeffe, Gerard W

    2014-06-01

    "Fetal programming" is a term used to describe how early-life experience influences fetal development and later disease risk. In humans, prenatal stress-induced fetal programming is associated with increased risk of preterm birth, and a heightened risk of metabolic and neurological diseases later in life. A critical determinant of this is the regulation of fetal exposure to glucocorticoids by the placenta. Glucocorticoids are the mediators through which maternal stress influences fetal development. Excessive fetal glucocorticoid exposure during pregnancy results in low birth weight and abnormalities in a number of tissues. The amount of fetal exposure to maternal glucocorticoids depends on the expression of HSD11B2, an enzyme predominantly produced by the syncytiotrophoblast in the placenta. This protects the fetus by converting active glucocorticoids into inactive forms. In this review we examine recent findings regarding placental HSD11B2 that suggest that its epigenetic regulation may mechanistically link maternal stress and long-term health consequences in affected offspring.

  20. Epigenetic regulation of the placental HSD11B2 barrier and its role as a critical regulator of fetal development

    PubMed Central

    Togher, Katie L; Togher, Katie L; O'Keeffe, Majella M; O'Keeffe, Majella M; Khashan, Ali S; Khashan, Ali S; Gutierrez, Humberto; Gutierrez, Humberto; Kenny, Louise C; Kenny, Louise C; O'Keeffe, Gerard W; O'Keeffe, Gerard W

    2014-01-01

    “Fetal programming” is a term used to describe how early-life experience influences fetal development and later disease risk. In humans, prenatal stress-induced fetal programming is associated with increased risk of preterm birth, and a heightened risk of metabolic and neurological diseases later in life. A critical determinant of this is the regulation of fetal exposure to glucocorticoids by the placenta. Glucocorticoids are the mediators through which maternal stress influences fetal development. Excessive fetal glucocorticoid exposure during pregnancy results in low birth weight and abnormalities in a number of tissues. The amount of fetal exposure to maternal glucocorticoids depends on the expression of HSD11B2, an enzyme predominantly produced by the syncytiotrophoblast in the placenta. This protects the fetus by converting active glucocorticoids into inactive forms. In this review we examine recent findings regarding placental HSD11B2 that suggest that its epigenetic regulation may mechanistically link maternal stress and long-term health consequences in affected offspring. PMID:24717516

  1. Pancreatic islet expression of chemokine CCL2 suppresses autoimmune diabetes via tolerogenic CD11c+ CD11b+ dendritic cells.

    PubMed

    Kriegel, Martin A; Rathinam, Chozhavendan; Flavell, Richard A

    2012-02-28

    Development of type 1 diabetes in the nonobese diabetic (NOD) mouse is preceded by an immune cell infiltrate in the pancreatic islets. The exact role of the attracted cells is still poorly understood. Chemokine CCL2/MCP-1 is known to attract CCR2(+) monocytes and dendritic cells (DCs). We have previously shown that transgenic expression of CCL2 in pancreatic islets via the rat insulin promoter induces nondestructive insulitis on a nonautoimmune background. We report here an unexpected reduction of diabetes development on the NOD background despite an increased islet cell infiltrate with markedly increased numbers of CD11c(+) CD11b(+) DCs. These DCs exhibited a hypoactive phenotype with low CD40, MHC II, CD80/CD86 expression, and reduced TNF-α but elevated IL-10 secretions. They failed to induce proliferation of diabetogenic CD4(+) T cells in vitro. Pancreatic lymph node CD4(+) T cells were down-regulated ex vivo and expressed the anergy marker Grail. By using an in vivo transfer system, we show that CD11c(+) CD11b(+) DCs from rat insulin promoter-CCL2 transgenic NOD mice were the most potent cells suppressing diabetes development. These findings support an unexpected beneficial role for CCL2 in type 1 diabetes with implications for current strategies interfering with the CCL2/CCR2 axis in humans, and for dendritic cell biology in autoimmunity.

  2. Rab11b mediates melanin transfer between donor melanocytes and acceptor keratinocytes via coupled exo/endocytosis.

    PubMed

    Tarafder, Abul K; Bolasco, Giulia; Correia, Maria S; Pereira, Francisco J C; Iannone, Lucio; Hume, Alistair N; Kirkpatrick, Niall; Picardo, Mauro; Torrisi, Maria R; Rodrigues, Inês P; Ramalho, José S; Futter, Clare E; Barral, Duarte C; Seabra, Miguel C

    2014-04-01

    The transfer of melanin from melanocytes to keratinocytes is a crucial process underlying maintenance of skin pigmentation and photoprotection against UV damage. Here, we present evidence supporting coupled exocytosis of the melanin core, or melanocore, by melanocytes and subsequent endocytosis by keratinocytes as a predominant mechanism of melanin transfer. Electron microscopy analysis of human skin samples revealed three lines of evidence supporting this: (1) the presence of melanocores in the extracellular space; (2) within keratinocytes, melanin was surrounded by a single membrane; and (3) this membrane lacked the melanosomal membrane protein tyrosinase-related protein 1 (TYRP1). Moreover, co-culture of melanocytes and keratinocytes suggests that melanin exocytosis is specifically induced by keratinocytes. Furthermore, depletion of Rab11b, but not Rab27a, caused a marked decrease in both keratinocyte-stimulated melanin exocytosis and transfer to keratinocytes. Thus, we propose that the predominant mechanism of melanin transfer is keratinocyte-induced exocytosis, mediated by Rab11b through remodeling of the melanosome membrane, followed by subsequent endocytosis by keratinocytes.

  3. NMR logging apparatus

    DOEpatents

    Walsh, David O; Turner, Peter

    2014-05-27

    Technologies including NMR logging apparatus and methods are disclosed. Example NMR logging apparatus may include surface instrumentation and one or more downhole probes configured to fit within an earth borehole. The surface instrumentation may comprise a power amplifier, which may be coupled to the downhole probes via one or more transmission lines, and a controller configured to cause the power amplifier to generate a NMR activating pulse or sequence of pulses. Impedance matching means may be configured to match an output impedance of the power amplifier through a transmission line to a load impedance of a downhole probe. Methods may include deploying the various elements of disclosed NMR logging apparatus and using the apparatus to perform NMR measurements.

  4. Human T-cell leukemia virus type 1 Tax oncoprotein represses the expression of the BCL11B tumor suppressor in T-cells.

    PubMed

    Takachi, Takayuki; Takahashi, Masahiko; Takahashi-Yoshita, Manami; Higuchi, Masaya; Obata, Miki; Mishima, Yukio; Okuda, Shujiro; Tanaka, Yuetsu; Matsuoka, Masao; Saitoh, Akihiko; Green, Patrick L; Fujii, Masahiro

    2015-04-01

    Human T-cell leukemia virus type 1 (HTLV-1) is the etiological agent of adult T cell leukemia (ATL), which is an aggressive form of T-cell malignancy. HTLV-1 oncoproteins, Tax and HBZ, play crucial roles in the immortalization of T-cells and/or leukemogenesis by dysregulating the cellular functions in the host. Recent studies show that HTLV-1-infected T-cells have reduced expression of the BCL11B tumor suppressor protein. In the present study, we explored whether Tax and/or HBZ play a role in downregulating BCL11B in HTLV-1-infected T-cells. Lentiviral transduction of Tax in a human T-cell line repressed the expression of BCL11B at both the protein and mRNA levels, whereas the transduction of HBZ had little effect on the expression. Tax mutants with a decreased activity for the NF-κB, CREB or PDZ protein pathways still showed a reduced expression of the BCL11B protein, thereby implicating a different function of Tax in BCL11B downregulation. In addition, the HTLV-2 Tax2 protein reduced the BCL11B protein expression in T-cells. Seven HTLV-1-infected T-cell lines, including three ATL-derived cell lines, showed reduced BCL11B mRNA and protein expression relative to an uninfected T-cell line, and the greatest reductions were in the cells expressing Tax. Collectively, these results indicate that Tax is responsible for suppressing BCL11B protein expression in HTLV-1-infected T-cells; Tax-mediated repression of BCL11B is another mechanism that Tax uses to promote oncogenesis of HTLV-1-infected T-cells.

  5. Human T-cell leukemia virus type 1 Tax oncoprotein represses the expression of the BCL11B tumor suppressor in T-cells

    PubMed Central

    Takachi, Takayuki; Takahashi, Masahiko; Takahashi-Yoshita, Manami; Higuchi, Masaya; Obata, Miki; Mishima, Yukio; Okuda, Shujiro; Tanaka, Yuetsu; Matsuoka, Masao; Saitoh, Akihiko; Green, Patrick L; Fujii, Masahiro

    2015-01-01

    Human T-cell leukemia virus type 1 (HTLV-1) is the etiological agent of adult T cell leukemia (ATL), which is an aggressive form of T-cell malignancy. HTLV-1 oncoproteins, Tax and HBZ, play crucial roles in the immortalization of T-cells and/or leukemogenesis by dysregulating the cellular functions in the host. Recent studies show that HTLV-1-infected T-cells have reduced expression of the BCL11B tumor suppressor protein. In the present study, we explored whether Tax and/or HBZ play a role in downregulating BCL11B in HTLV-1-infected T-cells. Lentiviral transduction of Tax in a human T-cell line repressed the expression of BCL11B at both the protein and mRNA levels, whereas the transduction of HBZ had little effect on the expression. Tax mutants with a decreased activity for the NF-κB, CREB or PDZ protein pathways still showed a reduced expression of the BCL11B protein, thereby implicating a different function of Tax in BCL11B downregulation. In addition, the HTLV-2 Tax2 protein reduced the BCL11B protein expression in T-cells. Seven HTLV-1-infected T-cell lines, including three ATL-derived cell lines, showed reduced BCL11B mRNA and protein expression relative to an uninfected T-cell line, and the greatest reductions were in the cells expressing Tax. Collectively, these results indicate that Tax is responsible for suppressing BCL11B protein expression in HTLV-1-infected T-cells; Tax-mediated repression of BCL11B is another mechanism that Tax uses to promote oncogenesis of HTLV-1-infected T-cells. PMID:25613934

  6. Closed-cycle cold helium magic-angle spinning for sensitivity-enhanced multi-dimensional solid-state NMR.

    PubMed

    Matsuki, Yoh; Nakamura, Shinji; Fukui, Shigeo; Suematsu, Hiroto; Fujiwara, Toshimichi

    2015-10-01

    Magic-angle spinning (MAS) NMR is a powerful tool for studying molecular structure and dynamics, but suffers from its low sensitivity. Here, we developed a novel helium-cooling MAS NMR probe system adopting a closed-loop gas recirculation mechanism. In addition to the sensitivity gain due to low temperature, the present system has enabled highly stable MAS (vR=4-12 kHz) at cryogenic temperatures (T=35-120 K) for over a week without consuming helium at a cost for electricity of 16 kW/h. High-resolution 1D and 2D data were recorded for a crystalline tri-peptide sample at T=40 K and B0=16.4 T, where an order of magnitude of sensitivity gain was demonstrated versus room temperature measurement. The low-cost and long-term stable MAS strongly promotes broader application of the brute-force sensitivity-enhanced multi-dimensional MAS NMR, as well as dynamic nuclear polarization (DNP)-enhanced NMR in a temperature range lower than 100 K.

  7. Dynamics and interactions of ibuprofen in cyclodextrin nanosponges by solid-state NMR spectroscopy.

    PubMed

    Ferro, Monica; Castiglione, Franca; Pastori, Nadia; Punta, Carlo; Melone, Lucio; Panzeri, Walter; Rossi, Barbara; Trotta, Francesco; Mele, Andrea

    2017-01-01

    Two different formulations of cyclodextrin nanosponges (CDNS), obtained by polycondensation of β-cyclodextrin with ethylenediaminetetraacetic acid dianhydride (EDTAn), were treated with aqueous solutions of ibuprofen sodium salt (IbuNa) affording hydrogels that, after lyophilisation, gave two solid CDNS-drug formulations. (1)H fast MAS NMR and (13)C CP-MAS NMR spectra showed that IbuNa was converted in situ into its acidic and dimeric form (IbuH) after freeze-drying. (13)C CP-MAS NMR spectra also indicated that the structure of the nanosponge did not undergo changes upon drug loading compared to the unloaded system. However, the (13)C NMR spectra collected under variable contact time cross-polarization (VCT-CP) conditions showed that the polymeric scaffold CDNS changed significantly its dynamic regime on passing from the empty CDNS to the drug-loaded CDNS, thus showing that the drug encapsulation can be seen as the formation of a real supramolecular aggregate rather than a conglomerate of two solid components. Finally, the structural features obtained from the different solid-state NMR approaches reported matched the information from powder X-ray diffraction profiles.

  8. Dynamics and interactions of ibuprofen in cyclodextrin nanosponges by solid-state NMR spectroscopy

    PubMed Central

    Ferro, Monica; Pastori, Nadia; Punta, Carlo; Melone, Lucio; Panzeri, Walter; Rossi, Barbara; Trotta, Francesco

    2017-01-01

    Two different formulations of cyclodextrin nanosponges (CDNS), obtained by polycondensation of β-cyclodextrin with ethylenediaminetetraacetic acid dianhydride (EDTAn), were treated with aqueous solutions of ibuprofen sodium salt (IbuNa) affording hydrogels that, after lyophilisation, gave two solid CDNS-drug formulations. 1H fast MAS NMR and 13C CP-MAS NMR spectra showed that IbuNa was converted in situ into its acidic and dimeric form (IbuH) after freeze-drying. 13C CP-MAS NMR spectra also indicated that the structure of the nanosponge did not undergo changes upon drug loading compared to the unloaded system. However, the 13C NMR spectra collected under variable contact time cross-polarization (VCT-CP) conditions showed that the polymeric scaffold CDNS changed significantly its dynamic regime on passing from the empty CDNS to the drug-loaded CDNS, thus showing that the drug encapsulation can be seen as the formation of a real supramolecular aggregate rather than a conglomerate of two solid components. Finally, the structural features obtained from the different solid-state NMR approaches reported matched the information from powder X-ray diffraction profiles. PMID:28228859

  9. Experimental evaluation of the isotopic exchange equilibrium 10B(OH) 3+ 11B(OH) 4-= 11B(OH) 3+ 10B(OH) 4- in aqueous solution

    NASA Astrophysics Data System (ADS)

    Byrne, Robert H.; Yao, Wensheng; Klochko, Kateryna; Tossell, John A.; Kaufman, Alan J.

    2006-04-01

    The precision of spectrophotometric measurements of indicator absorbance ratios is sufficient to allow evaluation of small isotopically induced differences in the dissociation constant of boric acid ( KB). The quotient of 11KB and 10KB, obtained using isotopically ⩾99% pure borate/boric acid buffers, provides an equilibrium constant for the reaction 10B(OH) 3+ 11B(OH) 4-⇔ 11B(OH) 3+ 10B(OH) 4- which heretofore had not been experimentally determined. Previous theoretical and semi-empirical evaluations of this equilibrium, which is important for assessments of the paleo-pH of seawater and the paleo- pCO 2 of the atmosphere, have yielded constants, 11-10KB= 10KB/ 11KB, that have ranged between 1.0194 and approximately 1.033. The experimentally determined value 11-10KB=1.028 5±0.001 6 (mean±95% confidence interval) obtained at 25 °C and 0.63 molal (mol kg -1 H 2O) ionic strength is in much better agreement with recent theoretical assessments of 11-10KB that have ranged between 1.026 and 1.033, than the much-cited original estimate (1.0194) of Kakihana et al. (1977) [Fundamental studies on the ion-exchange separation of boron isotopes. Bulletin of Chemical Society of Japan 50, 158-163]. Since the activity quotient for the fractionation reaction is almost equal to unity, it is expected that the 11-10KB value obtained in this study will be applicable over a wide range of solution compositions and ionic strengths.

  10. In Vivo Detection of the Cyclic Osmoregulated Periplasmic Glucan of Ralstonia solanacearum by High-Resolution Magic Angle Spinning NMR

    NASA Astrophysics Data System (ADS)

    Wieruszeski, J.-M.; Bohin, A.; Bohin, J.-P.; Lippens, G.

    2001-07-01

    We investigate the mobility of the osmoregulated periplasmic glucans of Ralstonia solanacearum in the bacterial periplasm through the use of high-resolution (HR) NMR spectroscopy under static and magic angle spinning (MAS) conditions. Because the nature of periplasm is far from an isotropic aqueous solution, the molecules could be freely diffusing or rather associated to a periplasmic protein, a membrane protein, a lipid, or the peptidoglycan. HR MAS NMR spectroscopy leads to more reproducible results and allows the in vivo detection and characterization of the complex molecule.

  11. Al coordination and water speciation in hydrous aluminosilicate glasses: direct evidence from high-resolution heteronuclear 1H-27Al correlation NMR.

    PubMed

    Xue, Xianyu; Kanzaki, Masami

    2007-02-01

    In order to shed light on the dissolution mechanisms of water in depolymerized aluminosilicate melts/glasses, a comprehensive one- (1D) and two-dimensional (2D) NMR study has been carried out on hydrous Ca- and Mg-aluminosilicate glasses of a haplobasaltic composition. The applied techniques include 1D 1H MAS NMR and 27Al-->1H cross-polarization (CP) MAS NMR, and 2D 1H NOESY and double-quantum (DQ) MAS NMR, 27Al triple-quantum (3Q) MAS NMR and 27Al-->1H heteronuclear correlation (HETCOR) and 3QMAS/HETCOR NMR. Ab initio calculations were also performed to place additional constraints on the 1H NMR characteristics of AlOH and Si(OH)Al groups. This study has revealed, for the first time, the presence of free OH (i.e. (Ca, Mg)OH), SiOH and AlOH species, in addition to molecular H2O, in hydrous glasses of a depolymerized aluminosilicate composition. The AlOH groups are mostly associated with four-coordinate Al, but some are associated with five- and six-coordinate Al.

  12. Simultaneous mobilization of Mac-1 (CD11b/CD18) and formyl peptide chemoattractant receptors in human neutrophils.

    PubMed

    Graves, V; Gabig, T; McCarthy, L; Strour, E F; Leemhuis, T; English, D

    1992-08-01

    Mobilization of a distinct subset of specific granules provides a physiologically important mechanism to recruit Mac-1 (CD11b/CD18) from an intracellular pool to the external surface of the neutrophil plasma membrane, where the functionally active heterodimer mediates several adherence-dependent processes that are crucial for adequate host defense and cellular inflammatory responses. We observed similar characteristics for translocation of Mac-1 and neutrophil formyl peptide receptors (FPR) and hypothesize that the readily accessible pools of both Mac-1 and FPR are colocalized within this specific granule subset. Plasma membrane levels of both FPR (assessed with 3H-FMLP) and Mac-1 (assessed by fluorescence-activated cell sorter analysis of fluorescein isothiocyanate [FITC]-Mo-1-labeled cells) were markedly downregulated in cells prepared at low temperature from blood cooled to 4 degrees C immediately after removal from the circulation. Levels of both FPR and Mac-1 remained low on cells held at 4 degrees C. Upon warming, spontaneous upregulation of Mac-1 and FPR occurred with similar kinetics and temperature dependency. Translocation of both Mac-1 and FPR was markedly potentiated by exposure of cells to either fluoride ion (which has been shown by others to specifically elicit exocytosis of gelatinase-rich and vitamin B-12 binding protein-poor granules) or granulocyte-macrophage colony-stimulating factor (GM-CSF), a cytokine that markedly potentiates the neutrophils' host defense capabilities. Levels of both FPR and Mac-1 on F-- or GM-CSF-treated neutrophils exceeded those present on cells incubated at 37 degrees C for extended time intervals, indicating that stimulated translocation may involve mobilization of an additional granule subset. Scatchard analysis showed that only low-affinity FPR were translocated during spontaneous and stimulus-dependent upregulation. To directly compare FPR levels on the surface of cells displaying varying levels of Mac-1 within a

  13. Cross section asymmetry of two-body carbon disintegration 12C (γ , p)11B with polarized photons at energy 40-50 MeV

    NASA Astrophysics Data System (ADS)

    Burdeinyi, D.; Brudvik, J.; Fissum, K.; Ganenko, V.; Hansen, K.; Isaksson, L.; Livingston, K.; Lundin, M.; Nilsson, B.; Schroder, B.

    2017-01-01

    The cross section asymmetry of 12C (γ ,p01)11B and 12C (γ ,p2-6)11B reactions has been studied at the energy range 40-55 MeV, using linearly polarized tagged photons of the MAX-lab facility. The asymmetry of the 12C (γ ,p01)11B processes, which assume the one-body mechanism of the reaction, is Σ ≈ 0.82 ± 0.05 for photon energies 45-50 MeV. The asymmetry for the 12C (γ ,p2-6)11B reactions, which produce a maximum at excitation energy ∼ 6 MeV, is Σ ≈ 0.53 ± 0.13 for a photon energy 49 MeV. It is close to the asymmetry of reaction of the free deuteron photodisintegration, and can be resulted from the two-body mechanism of the photon absorption.

  14. Commercial facility site selection simulating based on MAS

    NASA Astrophysics Data System (ADS)

    Chao, Yi; Li, Qingquan; Zheng, Guizhou

    2008-10-01

    The location of commercial facility decides the benefit of the operator to a large degree. Existing location methods can express the static relationships between site selection result and location factors, but there still are some limites when express the dynamic and uncertain relationship between them. Hence, a dynamic, stochastic and forecastable location model should be built which can introduce the customer's behavior into the model and combine the macro pattern and micro spatial interaction. So the authors proposes Geosim-LM based on MAS. Geosim-LM has 3 kinds of agents, CustAgent, SiteAgent and GovAgent. They represent the customers, commercial fercilities and government. The land type, land price and traffic are the model environment. Then Geosim-LM is applied in the bank branches site evaluation and selection in Liwan district, Guangzhou. In existing bank branches site evaluation, there are 70% consistent in score grade between result of Geosim-LM after 200 round runing and actual rebust location. It proves the model is reliable and feasible. The conclusions can be get from the paper. MAS have advantages in location choice than existed methods. The result of Geosim-LM running can powerfully proves that building location model based on MAS is feasible.

  15. Structure vs. composition: A solid-state 1H and 29Si NMR study of quenched glasses along the Na 2O-SiO 2-H 2O join

    NASA Astrophysics Data System (ADS)

    Cody, George D.; Mysen, Bjorn O.; Lee, Sung Keun

    2005-05-01

    A suite of six hydrous (7 wt.% H 2O) sodium silicate glasses spanning sodium octasilicate to sodium disilicate in composition were analyzed using 29Si single pulse (SP) magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy, 1H- 29Si cross polarization (CP) MAS NMR, and fast MAS 1H-NMR. From the 29Si SPMAS data it is observed that at low sodium compositions dissolved water significantly depolymerizes the silicate network. At higher sodium contents, however, dissolved H 2O does not affect a significant increase in depolymerization over that predicted based on the Na/Si ratio alone. The fast MAS 1H-NMR data reveal considerable complexity in proton environments in each of the glasses studied. The fast MAS 1H-NMR spectra of the highest sodium concentration glasses do not exhibit evidence of signficantly greater fractions of dissolved water as molecular H 2O than the lower sodium concentration glasses requiring that the decrease in polymerization at high sodium contents involves a change in sodium solution mechanism. Variable contact time 1H- 29Si cross polarization (CP) MAS NMR data reveal an increase in the rotating frame spin lattice relaxation rate constant ( T1ρ*) for various Q n species with increasing sodium content that correlates with a reduction in the average 1H- 29Si coupling strength. At the highest sodium concentration, however, T1ρ* drops significantly, consistent with a change in the Na 2O solution mechanism.

  16. The cAMP pathway regulates mRNA decay through phosphorylation of the RNA-binding protein TIS11b/BRF1

    PubMed Central

    Rataj, Felicitas; Planel, Séverine; Desroches-Castan, Agnès; Le Douce, Juliette; Lamribet, Khadija; Denis, Josiane; Feige, Jean-Jacques; Cherradi, Nadia

    2016-01-01

    TPA-inducible sequence 11b/butyrate response factor 1 (TIS11b/BRF1) belongs to the tristetraprolin (TTP) family of zinc-finger proteins, which bind to mRNAs containing AU-rich elements in their 3′-untranslated region and target them for degradation. Regulation of TTP family function through phosphorylation by p38 MAP kinase and Akt/protein kinase B signaling pathways has been extensively studied. In contrast, the role of cAMP-dependent protein kinase (PKA) in the control of TTP family activity in mRNA decay remains largely unknown. Here we show that PKA activation induces TIS11b gene expression and protein phosphorylation. Site-directed mutagenesis combined with kinase assays and specific phosphosite immunodetection identified Ser-54 (S54) and Ser-334 (S334) as PKA target amino acids in vitro and in vivo. Phosphomimetic mutation of the C-terminal S334 markedly increased TIS11b half-life and, unexpectedly, enhanced TIS11b activity on mRNA decay. Examination of protein–protein interactions between TIS11b and components of the mRNA decay machinery revealed that mimicking phosphorylation at S334 enhances TIS11b interaction with the decapping coactivator Dcp1a, while preventing phosphorylation at S334 potentiates its interaction with the Ccr4-Not deadenylase complex subunit Cnot1. Collectively our findings establish for the first time that cAMP-elicited phosphorylation of TIS11b plays a key regulatory role in its mRNA decay-promoting function. PMID:27708140

  17. cAMP-dependent posttranscriptional regulation of steroidogenic acute regulatory (STAR) protein by the zinc finger protein ZFP36L1/TIS11b.

    PubMed

    Duan, Haichuan; Cherradi, Nadia; Feige, Jean-Jacques; Jefcoate, Colin

    2009-04-01

    Star is expressed in steroidogenic cells as 3.5- and 1.6-kb transcripts that differ only in their 3'-untranslated regions (3'-UTR). In mouse MA10 testis and Y-1 adrenal lines, Br-cAMP preferentially stimulates 3.5-kb mRNA. ACTH is similarly selective in primary bovine adrenocortical cells. The 3.5-kb form harbors AU-rich elements (AURE) in the extended 3'-UTR, which enhance turnover. After peak stimulation of 3.5-kb mRNA, degradation is seen. Star mRNA turnover is enhanced by the zinc finger protein ZFP36L1/TIS11b, which binds to UAUUUAUU repeats in the extended 3'-UTR. TIS11b is rapidly stimulated in each cell type in parallel with Star mRNA. Cotransfection of TIS11b selectively decreases cytomegalovirus-promoted Star mRNA and luciferase-Star 3'-UTR reporters harboring the extended 3'-UTR. Direct complex formation was demonstrated between TIS11b and the extended 3'-UTR of the 3.5-kb Star. AURE mutations revealed that TIS11b-mediated destabilization required the first two UAUUUAUU motifs. HuR, which also binds AURE, did not affect Star expression. Targeted small interfering RNA knockdown of TIS11b specifically enhanced stimulation of 3.5-kb Star mRNA in bovine adrenocortical cells, MA-10, and Y-1 cells but did not affect the reversals seen after peak stimulation. Direct transfection of Star mRNA demonstrated that Br-cAMP stimulated a selective turnover of 3.5-kb mRNA independent of AURE, which may correspond to these reversal processes. Steroidogenic acute regulatory (STAR) protein induction was halved by TIS11b knockdown, concomitant with decreased cholesterol metabolism. TIS11b suppression of 3.5-kb mRNA is therefore surprisingly coupled to enhanced Star translation leading to increased cholesterol metabolism.

  18. 8Li({alpha},n)11B at Big Bang Temperatures: Neutron Counting With a Low Intensity 8Li Radioactive Beam

    SciTech Connect

    Cherubini, S.; Rolfs, C.; Strieder, F.; Figuera, P.; Agodi, C.; Alba, R.; Calabretta, L.; Cosentino, L.; Del Zoppo, A.; Di Pietro, A.; Lamia, L.; Pappalardo, L.; Pizzone, R.G.; Musumarra, A.; Pellegriti, M.G.; Rinollo, A.; Romano, S.; Spitaleri, C.; Tudisco, S.; Tumino, A.

    2004-02-27

    The cross section of 8Li({alpha},n)11B is very important for the study of primordial nucleosinthesys models. In this paper we report on the production of a 8Li beam via the 7Li(d,p)8Li reaction at the Laboratori Nazionali del Sud. Also, a novel experimental technique for measuring the reaction 8Li({alpha},n)11B at energies of astrophysical interest has been implemented and tested.

  19. HAT-P-11b: A SUPER-NEPTUNE PLANET TRANSITING A BRIGHT K STAR IN THE KEPLER FIELD

    SciTech Connect

    Bakos, G. A.; Torres, G.; Pal, A.; Hartman, J.; Noyes, R. W.; Latham, D. W.; Sasselov, D. D.; Sipocz, B.; Esquerdo, G. A.; Kovacs, Gabor; Fernandez, J.; Kovacs, Geza; Moor, A.; Fischer, D. A.; Isaacson, H.; Johnson, J. A.; Marcy, G. W.; Howard, A.; Butler, R. P.; Vogt, S.

    2010-02-20

    We report on the discovery of HAT-P-11b, the smallest radius transiting extrasolar planet (TEP) discovered from the ground, and the first hot Neptune discovered to date by transit searches. HAT-P-11b orbits the bright (V = 9.587) and metal rich ([Fe/H] = +0.31 +- 0.05) K4 dwarf star GSC 03561-02092 with P = 4.8878162 +- 0.0000071 days and produces a transit signal with depth of 4.2 mmag, the shallowest found by transit searches that is due to a confirmed planet. We present a global analysis of the available photometric and radial velocity (RV) data that result in stellar and planetary parameters, with simultaneous treatment of systematic variations. The planet, like its near-twin GJ 436b, is somewhat larger than Neptune (17 M{sub +}, 3.8 R{sub +}) both in mass M{sub p} = 0.081 +- 0.009 M{sub J}(25.8 +- 2.9 M{sub +}) and radius R{sub p} = 0.422 +- 0.014 R{sub J}(4.73 +- 0.16 R{sub +}). HAT-P-11b orbits in an eccentric orbit with e = 0.198 +- 0.046 and omega = 355.{sup 0}2 +- 17.{sup 0}3, causing a reflex motion of its parent star with amplitude 11.6 +- 1.2 m s{sup -1}, a challenging detection due to the high level of chromospheric activity of the parent star. Our ephemeris for the transit events is T{sub c} = 2454605.89132 +- 0.00032 (BJD), with duration 0.0957 +- 0.0012 days, and secondary eclipse epoch of 2454608.96 +- 0.15 days (BJD). The basic stellar parameters of the host star are M{sub *} = 0.809{sup +0.020}{sub -0.027} M{sub sun}, R{sub *} = 0.752 +- 0.021 R{sub sun}, and T{sub eff*} = 4780 +- 50 K. Importantly, HAT-P-11 will lie on one of the detectors of the forthcoming Kepler mission; this should make possible fruitful investigations of the detailed physical characteristic of both the planet and its parent star at unprecedented precision. We discuss an interesting constraint on the eccentricity of the system by the transit light curve and stellar parameters. This will be particularly useful for eccentric TEPs with low-amplitude RV variations in Kepler

  20. Preclinical and Early Clinical Profile of a Highly Selective and Potent Oral Inhibitor of Aldosterone Synthase (CYP11B2)

    PubMed Central

    Schwab, Dietmar; Delporte, Marie-Laure; Palermo, Giuseppe; Amrein, Kurt; Mohr, Susanne; De Vera Mudry, Maria Cristina; Brown, Morris J.; Ferber, Philippe

    2017-01-01

    Primary hyperaldosteronism is a common cause of resistant hypertension. Aldosterone is produced in the adrenal by aldosterone synthase (AS, encoded by the gene CYP11B2). AS shares 93% homology to 11β-hydroxylase (encoded by the gene CYP11B1), responsible for cortisol production. This homology has hitherto impeded the development of a drug, which selectively suppresses aldosterone but not cortisol production, as a new treatment for primary hyperaldosteronism. We now report the development of RO6836191 as a potent (Ki 13 nmol/L) competitive inhibitor of AS, with in vitro selectivity >100-fold over 11β-hydroxylase. In cynomolgus monkeys challenged with synthetic adrenocorticotropic hormone, single doses of RO6836191 inhibited aldosterone synthesis without affecting the adrenocorticotropic hormone–induced rise in cortisol. In repeat-dose toxicity studies in monkeys, RO6836191 reproduced the adrenal changes of the AS−/− mouse: expansion of the zona glomerulosa; increased expression of AS (or disrupted green fluorescent protein gene in the AS−/− mouse); hypertrophy, proliferation, and apoptosis of zona glomerulosa cells. These changes in the monkey were partially reversible and partially preventable by electrolyte supplementation and treatment with an angiotensin-converting enzyme inhibitor. In healthy subjects, single doses of RO6836191, across a 360-fold dose range, reduced plasma and urine aldosterone levels with maximum suppression at a dose of 10 mg, but unchanged cortisol, on adrenocorticotropic hormone challenge, up to 360 mg, and increase in the precursors 11-deoxycorticosterone and 11-deoxycortisol only at or >90 mg. In conclusion, RO6836191 demonstrates that it is possible to suppress aldosterone production completely in humans without affecting cortisol production. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT01995383. PMID:27872236

  1. Evolution of magnetic properties and microstructure of Hf{sub 2}Co{sub 11}B alloys

    SciTech Connect

    McGuire, Michael A. Rios, Orlando

    2015-02-07

    Amorphous Hf{sub 2}Co{sub 11}B alloys produced by melt-spinning have been crystallized by annealing at 500–800 °C, and the products have been investigated using magnetization measurements, x-ray diffraction, and scanning electron microscopy. The results reveal the evolution of the phase fractions, microstructure, and magnetic properties with both annealing temperature and time. Crystallization of the phase denoted HfCo{sub 7}, which is associated with the development of coercivity, occurs slowly at 500 °C. Annealing at intermediate temperatures produces mixed phase samples containing some of the HfCo{sub 7} phase with the highest values of remanent magnetization and coercivity. The equilibrium structure at 800 °C contains HfCo{sub 3}B{sub 2}, Hf{sub 6}Co{sub 23}, and Co, and displays soft ferromagnetism. Maximum values for the remanent magnetization, intrinsic coercivity, and magnetic energy product among the samples are approximately 5.2 kG, 2.0 kOe, and 3.1 MGOe, respectively, which indicates that the significantly higher values observed in crystalline, melt-spun Hf{sub 2}Co{sub 11}B ribbons are a consequence of the non-equilibrium solidification during the melt-spinning process. Application of high magnetic fields during annealing is observed to strongly affect the microstructural evolution, which may provide access to higher performance materials in Zr/Hf-Co hard ferromagnets. The crystal structure of HfCo{sub 7} and the related Zr analogues is unknown, and without knowledge of atomic positions powder diffraction cannot distinguish among proposed unit cells and symmetries found in the literature.

  2. Anti-CD11b monoclonal antibody reduces ischemic cell damage after transient focal cerebral ischemia in rat.

    PubMed

    Chen, H; Chopp, M; Zhang, R L; Bodzin, G; Chen, Q; Rusche, J R; Todd, R F

    1994-04-01

    We investigated the effect of an anti-CD11b monoclonal antibody (1B6c) on ischemic cell damage after transient middle cerebral artery occlusion. We divided animals into three groups: MAb 1 group (n = 5)--rats were subjected to 2 hours of transient occlusion and 1B6c (1 mg/kg) was administered intravenously at 0 and 22 hours of reperfusion; MAb 2 group (n = 5)--same experimental protocol as MAb 1 group, except that the initial dose of 1B6c was increased to 2 mg/kg; and control group (n = 5)--same experimental protocol as MAb 2 group, except that an isotype-matched control antibody was administered. Animals were weighed and tested for neurological function before and after occlusion of the middle cerebral artery. Forty-six hours after reperfusion, brain sections were stained with hematoxylin and eosin for histology evaluation. We observed a significant reduction of weight loss and improvement in neurological function after ischemia in the MAb 2 animals compared to MAb 1 and vehicle-treated animals (p < 0.05). The lesion volume was significantly smaller in the MAb 2 group (19.5 +/- 1.9%) compared to MAb 1 (29.9 +/- 2.6%) and vehicle-treated (34.2 +/- 5.4%) groups (p < 0.01). Tissue polymorphonuclear cell numbers were reduced in both 1B6c-administered groups. Our data demonstrate that administration of anti-CD11b antibody results in a dose-dependent, significant functional improvement and reduction of ischemic cell damage after transient focal cerebral ischemia in the rat.

  3. Improvement in the transport critical current density and microstructure of isotopic Mg11B2 monofilament wires by optimizing the sintering temperature

    NASA Astrophysics Data System (ADS)

    Qiu, Wenbin; Jie, Hyunseock; Patel, Dipak; Lu, Yao; Luzin, Vladimir; Devred, Arnaud; Somer, Mehmet; Shahabuddin, Mohammed; Kim, Jung Ho; Ma, Zongqing; Dou, Shi Xue; Hossain, Md. Shahriar Al

    2016-11-01

    Superconducting wires are widely used in fabricating magnetic coils in fusion reactors. In consideration of the stability of 11B against neutron irradiation and lower induced radio-activation properties, MgB2 superconductor with 11B serving as boron source is an alternative candidate to be used in fusion reactor with severe irradiation environment. In present work, a batch of monofilament isotopic Mg11B2 wires with amorphous 11B powder as precursor were fabricated using powder-in-tube (PIT) process at different sintering temperature, and the evolution of their microstructure and corresponding superconducting properties was systemically investigated. Accordingly, the best transport critical current density (Jc) = 2 × 104 A/cm2 was obtained at 4.2 K and 5 T, which is even comparable to multi-filament Mg11B2 isotope wires reported in other work. Surprisingly, transport Jc vanished in our wire which was heat-treated at excessively high temperature (800 °C). Combined with microstructure observation, it was found that lots of big interconnected microcracks and voids that can isolate the MgB2 grains formed in this whole sample, resulting in significant deterioration in inter-grain connectivity. The results can be a constructive guide in fabricating Mg11B2 wires to be used as magnet coils in fusion reactor systems such as ITER-type tokamak magnet.

  4. Improvement in the transport critical current density and microstructure of isotopic Mg(11)B2 monofilament wires by optimizing the sintering temperature.

    PubMed

    Qiu, Wenbin; Jie, Hyunseock; Patel, Dipak; Lu, Yao; Luzin, Vladimir; Devred, Arnaud; Somer, Mehmet; Shahabuddin, Mohammed; Kim, Jung Ho; Ma, Zongqing; Dou, Shi Xue; Hossain, Md Shahriar Al

    2016-11-08

    Superconducting wires are widely used in fabricating magnetic coils in fusion reactors. In consideration of the stability of (11)B against neutron irradiation and lower induced radio-activation properties, MgB2 superconductor with (11)B serving as boron source is an alternative candidate to be used in fusion reactor with severe irradiation environment. In present work, a batch of monofilament isotopic Mg(11)B2 wires with amorphous (11)B powder as precursor were fabricated using powder-in-tube (PIT) process at different sintering temperature, and the evolution of their microstructure and corresponding superconducting properties was systemically investigated. Accordingly, the best transport critical current density (Jc) = 2 × 10(4) A/cm(2) was obtained at 4.2 K and 5 T, which is even comparable to multi-filament Mg(11)B2 isotope wires reported in other work. Surprisingly, transport Jc vanished in our wire which was heat-treated at excessively high temperature (800 °C). Combined with microstructure observation, it was found that lots of big interconnected microcracks and voids that can isolate the MgB2 grains formed in this whole sample, resulting in significant deterioration in inter-grain connectivity. The results can be a constructive guide in fabricating Mg(11)B2 wires to be used as magnet coils in fusion reactor systems such as ITER-type tokamak magnet.

  5. Improvement in the transport critical current density and microstructure of isotopic Mg11B2 monofilament wires by optimizing the sintering temperature

    PubMed Central

    Qiu, Wenbin; Jie, Hyunseock; Patel, Dipak; Lu, Yao; Luzin, Vladimir; Devred, Arnaud; Somer, Mehmet; Shahabuddin, Mohammed; Kim, Jung Ho; Ma, Zongqing; Dou, Shi Xue; Hossain, Md. Shahriar Al

    2016-01-01

    Superconducting wires are widely used in fabricating magnetic coils in fusion reactors. In consideration of the stability of 11B against neutron irradiation and lower induced radio-activation properties, MgB2 superconductor with 11B serving as boron source is an alternative candidate to be used in fusion reactor with severe irradiation environment. In present work, a batch of monofilament isotopic Mg11B2 wires with amorphous 11B powder as precursor were fabricated using powder-in-tube (PIT) process at different sintering temperature, and the evolution of their microstructure and corresponding superconducting properties was systemically investigated. Accordingly, the best transport critical current density (Jc) = 2 × 104 A/cm2 was obtained at 4.2 K and 5 T, which is even comparable to multi-filament Mg11B2 isotope wires reported in other work. Surprisingly, transport Jc vanished in our wire which was heat-treated at excessively high temperature (800 °C). Combined with microstructure observation, it was found that lots of big interconnected microcracks and voids that can isolate the MgB2 grains formed in this whole sample, resulting in significant deterioration in inter-grain connectivity. The results can be a constructive guide in fabricating Mg11B2 wires to be used as magnet coils in fusion reactor systems such as ITER-type tokamak magnet. PMID:27824144

  6. Solid-state NMR identification and quantification of newly formed aluminosilicate phases in weathered kaolinite systems.

    PubMed

    Crosson, Garry S; Choi, Sunkyung; Chorover, Jon; Amistadi, Mary Kay; O'Day, Peggy A; Mueller, Karl T

    2006-01-19

    The weathering of a specimen kaolinite clay was studied over the course of 369 d via solid-state 29Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy and high-field 27Al MAS NMR. The chosen baseline solution conditions (0.05 mol kg-1 of Al, 2 mol kg-1 of Na+, 1 mol kg-1 of NO3-, 1 mol kg-1 of OH-, and pH approximately 13.8) approximate those of solutions leaking from waste tanks at the Hanford Site in Richland, WA. Nonradioactive Cs and Sr cations were added to this synthetic tank waste leachate (STWL) solution at concentrations of 10(-3), 10(-4), and 10(-5) molal (m) to represent their radionuclide counterparts. The transformations of silicon- and aluminum-containing solid phase species were monitored quantitatively by using NMR spectroscopy, with the resulting spectra directly reporting the influence of the initial Cs and Sr on formation and transformation of the neo-formed solids. At the lowest concentration of Cs and Sr employed (10(-5) m in each cation) peaks consistent with the formation of zeolite-like minerals were detected via 29Si and 27Al MAS NMR as early as 33 d. At concentrations of 10(-3) m in each cation, new silicon species are not detected until 93 d, although neophases containing four-coordinate aluminum were detectable at earlier reaction times via 27Al MAS NMR. At the highest magnetic field strengths employed in this NMR study, deconvolutions of resonances detected in the tetrahedral region of the 27Al MAS spectra yielded multiple components, indicating the existence of at least four new aluminum-containing phases. Two of these phases are identified as sodalite and cancrinite through comparison with diffuse-reflectance infrared (DRIFT) spectra and powder X-ray diffraction (XRD) results, while a third phase may correlate with a previously detected aluminum-rich chabazite phase. All measurable solid reaction products have been quantified via their 27Al MAS resonances acquired at high magnetic field strengths (17.6 T), and

  7. Solid-State NMR Identification and Quantification of Newly Formed Aluminosilicate Phases in Weathered Kaolinite Systems

    SciTech Connect

    Crosson, Garry S.; Choi, Sunkyung; Chorover, Jon; Amistadi, Mary K.; O'Day, Peggy A.; Mueller, Karl T.

    2006-01-19

    The weathering of a specimen kaolinite clay was studied over the course of 369 d via solid-state 29Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy and high-field 27Al MAS NMR. The chosen baseline solution conditions (0.05 mol kg-1 of Al, 2 mol kg-1 of Na+, 1 mol kg-1 of NO3 -, 1 mol kg-1 of OH-, and pH ~13.8) approximate those of solutions leaking from waste tanks at the Hanford Site in Richland, WA. Nonradioactive Cs and Sr cations were added to this synthetic tank waste leachate (STWL) solution at concentrations of 10-3, 10-4, and 10-5 molal (m) to represent their radionuclide counterparts. The transformations of silicon- and aluminum-containing solid phase species were monitored quantitatively by using NMR spectroscopy, with the resulting spectra directly reporting the influence of the initial Cs and Sr on formation and transformation of the neo-formed solids. At the lowest concentration of Cs and Sr employed (10-5 m in each cation) peaks consistent with the formation of zeolite-like minerals were detected via 29Si and 27Al MAS NMR as early as 33 d. At concentrations of 10-3 m in each cation, new silicon species are not detected until 93 d, although neophases containing four-coordinate aluminum were detectable at earlier reaction times via 27Al MAS NMR. At the highest magnetic field strengths employed in this NMR study, deconvolutions of resonances detected in the tetrahedral region of the 27Al MAS spectra yielded multiple components, indicating the existence of at least four new aluminum-containing phases. Two of these phases are identified as sodalite and cancrinite through comparison with diffuse-reflectance infrared (DRIFT) spectra and powder X-ray diffraction (XRD) results, while a third phase may correlate with a previously detected aluminum-rich chabazite phase. All measurable solid reaction products have been quantified via their 27Al MAS resonances acquired at high magnetic field strengths (17.6 T), and the quantitative

  8. Biomolecular solid state NMR with magic-angle spinning at 25 K

    PubMed Central

    Thurber, Kent R.; Tycko, Robert

    2009-01-01

    A magic-angle spinning (MAS) probe has been constructed which allows the sample to be cooled with helium, while the MAS bearing and drive gases are nitrogen. The sample can be cooled to 25 K using roughly 3 liters/hour of liquid helium, while the 4 mm diameter rotor spins at 6.7 kHz with good stability (±5 Hz) for many hours. Proton decoupling fields up to at least 130 kHz can be applied. This helium-cooled MAS probe enables a variety of one-dimensional and two-dimensional NMR experiments on biomolecular solids and other materials at low temperatures, with signal-to-noise proportional to 1/T. We show examples of low-temperature 13C NMR data for two biomolecular samples, namely the peptide Aβ14–23 in the form of amyloid fibrils and the protein HP35 in frozen glycerol/water solution. Issues related to temperature calibration, spin-lattice relaxation at low temperatures, paramagnetic doping of frozen solutions, and 13C MAS NMR linewidths are discussed. PMID:18922715

  9. IN SITU MAGIC ANGLE SPINNING NMR FOR STUDYING GEOLOGICAL CO(2) SEQUESTRATION

    SciTech Connect

    Hoyt, David W.; Turcu, Romulus VF; Sears, Jesse A.; Rosso, Kevin M.; Burton, Sarah D.; Kwak, Ja Hun; Felmy, Andrew R.; Hu, Jian Z.

    2011-03-27

    Geological carbon sequestration (GCS) is one of the most promising ways of mitigating atmospheric greenhouse gases (1-3). Mineral carbonation reactions are potentially important to the long-term sealing effectiveness of caprock but remain poorly predictable, particularly in low-water supercritical CO2 (scCO2)-dominated environments where the chemistry has not been adequately explored. In situ probes that provide molecular-level information is desirable for investigating mechanisms and rates of GCS mineral carbonation reactions. MAS-NMR is a powerful tool for obtaining detailed molecular structure and dynamics information of a system regardless whether the system is in a solid, a liquid, a gaseous, or a supercritical state, or a mixture thereof (4,5). However, MAS NMR under scCO2 conditions has never been realized due to the tremendous technical difficulties of achieving and maintaining high pressure within a fast spinning MAS rotor (6,7), where non-metal materials must be used. In this work, we report development of a unique high pressure MAS NMR capability, and its application to mineral carbonation chemistry in scCO2 under geologically relevant temperatures and pressures.

  10. 99mTc-labelled anti-CD11b SPECT/CT imaging allows detection of plaque destabilization tightly linked to inflammation

    PubMed Central

    Liu, Guobing; Hu, Yan; Xiao, Jie; Li, Xiao; Li, Yanli; Tan, Hui; Zhao, Yanzhao; Cheng, Dengfeng; Shi, Hongcheng

    2016-01-01

    It remains challenging to predict the risk of rupture for a specific atherosclerotic plaque timely, a thrombotic trigger tightly linked to inflammation. CD11b, is a biomarker abundant on inflammatory cells, not restricted to monocytes/macrophages. In this study, we fabricated a probe named as 99mTc-MAG3-anti-CD11b for detecting inflamed atherosclerotic plaques with single photon emission computed tomography/computed tomography (SPECT/CT). The ApoE-knockout (ApoE−/−) mice were selected to establish animal models, with C57BL/6J mice used for control. A higher CD11b+-cell recruitment with higher CD11b expression and more serious whole-body inflammatory status were identified in ApoE−/− mice. The probe showed high in vitro affinity and specificity to the Raw-264.7 macrophages, as well as inflammatory cells infiltrated in atherosclerotic plaques, either in ex vivo fluorescent imaging or in in vivo micro-SPECT/CT imaging, which were confirmed by ex vivo planar gamma imaging, Oil-Red-O staining and CD11b-immunohistochemistry staining. A significant positive relationship was identified between the radioactivity intensity on SPECT/CT images and the CD11b expression in plaques. In summary, this study demonstrates the feasibility of anti-CD11b antibody mediated noninvasive SPECT/CT imaging of inflammatory leukocytes in murine atherosclerotic plaques. This imaging strategy can identify inflammation-rich plaques at risk for rupture and evaluate the effectiveness of inflammation-targeted therapies in atheroma. PMID:26877097

  11. Serum IL8 and mRNA level of CD11b in circulating neutrophils are increased in clinically amyopathic dermatomyositis with active interstitial lung disease.

    PubMed

    Zou, Jing; Chen, Jie; Yan, Qingran; Guo, Qiang; Bao, Chunde

    2016-01-01

    The objective of this study is to assess serum IL8 and the potential activity of circulating neutrophils on relative messenger RNA (mRNA) levels and their relationship with disease activity in clinically amyopathic dermatomyositis (CADM) associated with interstitial lung disease (ILD). We studied 18 CADM patients and compared them with 18 classic dermatomyositis (DM) patients and 18 healthy control subjects. Serum IL8 level and mRNA expressions of neutrophils (chemokine (C-X-C motif) receptor 1 (CXCR1), cluster of differentiation molecule 11b (CD11b), cluster of differentiation 64 (CD64), myeloid cell leukemia 1 (MCL1), interleukin-18 (IL18)) were detected. The overproduction of serum IL8 level was most significant in the CADM group with active period. The mRNA expressions of CD11b, IL18, and MCL1 were greatly increased in the neutrophils in patients with CADM compared with DM or healthy controls. Up-expressions of CD11b, IL18, and MCL1 were detected in the neutrophils in CADM patients of active period compared with remission period. A positive correlation was found between CD11b mRNA level and high-resolution computed tomography (HRCT) score, in CADM associated with ILD. Serum IL8 level and mRNA levels of CD11b, MCL1, and IL18 in circulating neutrophils are related with the disease activity of CADM-ILD. The mRNA level of CD11b is positively correlated with HRCT score in CADM-ILD.

  12. CD11c/CD18 Dominates Adhesion of Human Monocytes, Macrophages and Dendritic Cells over CD11b/CD18

    PubMed Central

    Ungai-Salánki, Rita; Orgován, Norbert; Szabó, Bálint; Horváth, Róbert; Erdei, Anna; Bajtay, Zsuzsa

    2016-01-01

    Complement receptors CR3 (CD11b/CD18) and CR4 (CD11c/CD18) belong to the family of beta2 integrins and are expressed mainly by myeloid cell types in humans. Previously, we proved that CR3 rather than CR4 plays a key role in phagocytosis. Here we analysed how CD11b and CD11c participate in cell adhesion to fibrinogen, a common ligand of CR3 and CR4, employing human monocytes, monocyte-derived macrophages (MDMs) and monocyte-derived dendritic cells (MDDCs) highly expressing CD11b as well as CD11c. We determined the exact numbers of CD11b and CD11c on these cell types by a bead-based technique, and found that the ratio of CD11b/CD11c is 1.2 for MDDCs, 1.7 for MDMs and 7.1 for monocytes, suggesting that the function of CD11c is preponderant in MDDCs and less pronounced in monocytes. Applying state-of-the-art biophysical techniques, we proved that cellular adherence to fibrinogen is dominated by CD11c. Furthermore, we found that blocking CD11b significantly enhances the attachment of MDDCs and MDMs to fibrinogen, demonstrating a competition between CD11b and CD11c for this ligand. On the basis of the cell surface receptor numbers and the measured adhesion strength we set up a model, which explains the different behavior of the three cell types. PMID:27658051

  13. CD11c/CD18 Dominates Adhesion of Human Monocytes, Macrophages and Dendritic Cells over CD11b/CD18.

    PubMed

    Sándor, Noémi; Lukácsi, Szilvia; Ungai-Salánki, Rita; Orgován, Norbert; Szabó, Bálint; Horváth, Róbert; Erdei, Anna; Bajtay, Zsuzsa

    Complement receptors CR3 (CD11b/CD18) and CR4 (CD11c/CD18) belong to the family of beta2 integrins and are expressed mainly by myeloid cell types in humans. Previously, we proved that CR3 rather than CR4 plays a key role in phagocytosis. Here we analysed how CD11b and CD11c participate in cell adhesion to fibrinogen, a common ligand of CR3 and CR4, employing human monocytes, monocyte-derived macrophages (MDMs) and monocyte-derived dendritic cells (MDDCs) highly expressing CD11b as well as CD11c. We determined the exact numbers of CD11b and CD11c on these cell types by a bead-based technique, and found that the ratio of CD11b/CD11c is 1.2 for MDDCs, 1.7 for MDMs and 7.1 for monocytes, suggesting that the function of CD11c is preponderant in MDDCs and less pronounced in monocytes. Applying state-of-the-art biophysical techniques, we proved that cellular adherence to fibrinogen is dominated by CD11c. Furthermore, we found that blocking CD11b significantly enhances the attachment of MDDCs and MDMs to fibrinogen, demonstrating a competition between CD11b and CD11c for this ligand. On the basis of the cell surface receptor numbers and the measured adhesion strength we set up a model, which explains the different behavior of the three cell types.

  14. Generation of antigen-presenting cells from tumor-infiltrated CD11b myeloid cells with DNA demethylating agent 5-aza-2'-deoxycytidine.

    PubMed

    Daurkin, Irina; Eruslanov, Evgeniy; Vieweg, Johannes; Kusmartsev, Sergei

    2010-05-01

    Tumor-recruited CD11b myeloid cells, including myeloid-derived suppressor cells, play a significant role in tumor progression, as these cells are involved in tumor-induced immune suppression and tumor neovasculogenesis. On the other hand, the tumor-infiltrated CD11b myeloid cells could potentially be a source of immunostimulatory antigen-presenting cells (APCs), since most of these cells represent common precursors of both dendritic cells and macrophages. Here, we investigated the possibility of generating mature APCs from tumor-infiltrated CD11b myeloid cells. We demonstrate that in vitro exposure of freshly excised mouse tumors to DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine (decitabine, AZA) results in selective elimination of tumor cells, but, surprisingly it also enriches CD45(+) tumor-infiltrated cells. The majority of "post-AZA" surviving CD45(+) tumor-infiltrated cells were represented by CD11b myeloid cells. A culture of isolated tumor-infiltrated CD11b cells in the presence of AZA and GM-CSF promoted their differentiation into mature F4/80/CD11c/MHC class II-positive APCs. These tumor-derived myeloid APCs produced substantially reduced amounts of immunosuppressive (IL-13, IL-10, PGE(2)), pro-angiogenic (VEGF, MMP-9) and pro-inflammatory (IL-1beta, IL-6, MIP-2) mediators than their precursors, freshly isolated tumor-infiltrated CD11b cells. Vaccinating naïve mice with ex vivo generated tumor-derived APCs resulted in the protection of 70% mice from tumor outgrowth. Importantly, no loading of tumor-derived APC with exogenous antigen was needed to stimulate T cell response and induce the anti-tumor effect. Collectively, our results for the first time demonstrate that tumor-infiltrated CD11b myeloid cells can be enriched and differentiated in the presence of DNA demethylating agent 5-aza-2'-deoxycytidine into mature tumor-derived APCs, which could be used for cancer immunotherapy.

  15. Assessment of Proton Microbeam Analysis of 11B for Quantitative Microdistribution Analysis of Boronated Neutron Capture Agent Analogs in Biological Tissues

    SciTech Connect

    Bench, G; Grant, P G; Ueda, D L; Autry-Conwell, S A; Hou, Y; Boggan, J E

    2002-12-04

    Purpose: To assess the {sup 11}B(p, {alpha}){sup 8}Be* nuclear reaction for quantitatively mapping the in-vivo sub-cellular distribution of boron within gliosarcoma tumors treated with boronated neutron capture therapy agent (NCTA) analogs. Materials and Methods: Intracranial tumors were produced in Fisher 344 rats using a 9L gliosarcoma model. Fourteen days later, the majority of rats were treated with f-boronophenylalanine and sacrificed 30 or 180 minutes after intravenous injection. Freeze dried tumor cryosections were imaged using the {sup 11}B(p, {alpha}){sup 8}Be* nuclear reaction and proton microbeams obtained from the nuclear microprobe at Lawrence Livermore National Laboratory. Results/Discussion: With{sup 11}B(p, {alpha}){sup 8}Be* analysis, {sup 11}B distributions within cells can be quantitatively imaged with spatial resolutions down to 1.5 {micro}m, minimum detection limits of 0.8 mg/kg and acquisition times of several hours. These capabilities offer advantages over alpha track autoradiography, electron energy loss spectroscopy and secondary ion mass spectrometry (SIMS) for 'B quantitation in tissues. However, the spatial resolution, multi-isotope capability and analysis times achieved with SIMS are superior to those achieved with {sup 11}B(p, {alpha}){sup 8}Be* analysis. Conclusions: When accuracy in quantitation is crucial, the assessing the microdistribution of {sup 11}B. {sup 11}B(p, {alpha}){sup 8}Be* reaction is well suited for Otherwise, SIMS may well be better suited to image the microdistribution of boron associated with NCTAs in biological tissues.

  16. The complement receptor 3 (CD11b/CD18) agonist Leukadherin‐1 suppresses human innate inflammatory signalling

    PubMed Central

    Roberts, A. L.; Fürnrohr, B. G.; Vyse, T. J.

    2016-01-01

    Summary Complement receptor 3 (CR3, CD11b/CD18) is a multi‐functional receptor expressed predominantly on myeloid and natural killer (NK) cells. The R77H variant of CD11b, encoded by the ITGAM rs1143679 polymorphism, is associated robustly with development of the autoimmune disease systemic lupus erythematosus (SLE) and impairs CR3 function, including its regulatory role on monocyte immune signalling. The role of CR3 in NK cell function is unknown. Leukadherin‐1 is a specific small‐molecule CR3 agonist that has shown therapeutic promise in animal models of vascular injury and inflammation. We show that Leukadherin‐1 pretreatment reduces secretion of interferon (IFN)‐γ, tumour necrosis factor (TNF) and macrophage inflammatory protein (MIP)‐1β by monokine‐stimulated NK cells. It was associated with a reduction in phosphorylated signal transducer and activator of transcription (pSTAT)‐5 following interleukin (IL)‐12 + IL‐15 stimulation (P < 0·02) and increased IL‐10 secretion following IL‐12 + IL‐18 stimulation (P < 0·001). Leukadherin‐1 pretreatment also reduces secretion of IL‐1β, IL‐6 and TNF by Toll‐like receptor (TLR)‐2 and TLR‐7/8‐stimulated monocytes (P < 0·01 for all). The R77H variant did not affect NK cell response to Leukadherin‐1 using ex‐vivo cells from homozygous donors; nor did the variant influence CR3 expression by these cell types, in contrast to a recent report. These data extend our understanding of CR3 biology by demonstrating that activation potently modifies innate immune inflammatory signalling, including a previously undocumented role in NK cell function. We discuss the potential relevance of this to the pathogenesis of SLE. Leukadherin‐1 appears to mediate its anti‐inflammatory effect irrespective of the SLE‐risk genotype of CR3, providing further evidence to support its evaluation of Leukadherin‐1 as a potential therapeutic for autoimmune disease. PMID:27118513

  17. NMR imaging microscopy

    SciTech Connect

    Not Available

    1986-10-01

    In the past several years, proton nuclear magnetic resonance (NMR) imaging has become an established technique in diagnostic medicine and biomedical research. Although much of the work in this field has been directed toward development of whole-body imagers, James Aguayo, Stephen Blackband, and Joseph Schoeninger of the Johns Hopkins University School of Medicine working with Markus Hintermann and Mark Mattingly of Bruker Medical Instruments, recently developed a small-bore NMR microscope with sufficient resolution to image a single African clawed toad cell (Nature 1986, 322, 190-91). This improved resolution should lead to increased use of NMR imaging for chemical, as well as biological or physiological, applications. The future of NMR microscopy, like that of many other newly emerging techniques, is ripe with possibilities. Because of its high cost, however, it is likely to remain primarily a research tool for some time. ''It's like having a camera,'' says Smith. ''You've got a way to look at things at very fine levels, and people are going to find lots of uses for it. But it is a very expensive technique - it costs $100,000 to add imaging capability once you have a high-resolution NMR, which itself is at least a $300,000 instrument. If it can answer even a few questions that can't be answered any other way, though, it may be well worth the cost.''

  18. Solid-state NMR characterization of Mowry Formation shales

    SciTech Connect

    Miknis, F.P.

    1992-04-01

    Solid-state {sup 13}C and {sup 29}Si NMR measurements were carried out on a series of petroleum source rocks from the Mowry Formation of the Powder River Basin in Wyoming. The objectives of this study wereto use CP/MAS {sup 13}C NMR measurements to monitor changes in the carbon structure of the kerogen that result from depth of burial, and to examine the feasibility of {sup 29}Si NMR for studying the thermal alteration of clay minerals during diagenesis. Carbon and silicon NMR measurements were made on a suite of samples covering a present-day depth interval of 3,000 to 11,500 ft.In general, the NMR results endorsed other geochemical analyses that were performed on the source rocks as part of another study to examine pressure compartmentalization in the Mowry Formation. The carbon aromaticity of the kerogen increased with depth of burial, and at depths greater that approximately 10,000 ft the kerogen showed little capacity to generate additional oil because of the small fraction of residual aliphatic carbon. By combining NMR and Rock-Eval measurements, an estimate of the hydrogen budget was obtained. The calculations indicated that approximately 20% of the kerogen was converted to hydrocarbons, and that sufficient hydrogen was liberated from aromatization and condensation reactions to stabilize the generated products. The {sup 29}Si NMR spectra were characterized by a relatively sharp quartz resonance and a broad resonance from the clay minerals. With increasing depth of burial, the clay resonance became broader and shifted slightly downfield. These changes qualitatively support X-ray analysis that shows progressive alteration of illite to smectite with depth of burial.

  19. Solid-state NMR characterization of Mowry Formation shales

    SciTech Connect

    Miknis, F.P.

    1992-04-01

    Solid-state [sup 13]C and [sup 29]Si NMR measurements were carried out on a series of petroleum source rocks from the Mowry Formation of the Powder River Basin in Wyoming. The objectives of this study wereto use CP/MAS [sup 13]C NMR measurements to monitor changes in the carbon structure of the kerogen that result from depth of burial, and to examine the feasibility of [sup 29]Si NMR for studying the thermal alteration of clay minerals during diagenesis. Carbon and silicon NMR measurements were made on a suite of samples covering a present-day depth interval of 3,000 to 11,500 ft.In general, the NMR results endorsed other geochemical analyses that were performed on the source rocks as part of another study to examine pressure compartmentalization in the Mowry Formation. The carbon aromaticity of the kerogen increased with depth of burial, and at depths greater that approximately 10,000 ft the kerogen showed little capacity to generate additional oil because of the small fraction of residual aliphatic carbon. By combining NMR and Rock-Eval measurements, an estimate of the hydrogen budget was obtained. The calculations indicated that approximately 20% of the kerogen was converted to hydrocarbons, and that sufficient hydrogen was liberated from aromatization and condensation reactions to stabilize the generated products. The [sup 29]Si NMR spectra were characterized by a relatively sharp quartz resonance and a broad resonance from the clay minerals. With increasing depth of burial, the clay resonance became broader and shifted slightly downfield. These changes qualitatively support X-ray analysis that shows progressive alteration of illite to smectite with depth of burial.

  20. Solid state (13)C NMR analysis of human gallstones from cancer and benign gall bladder diseases.

    PubMed

    Jayalakshmi, K; Sonkar, Kanchan; Behari, Anu; Kapoor, V K; Sinha, Neeraj

    2009-09-01

    Natural abundance (13)C cross polarized (CP) magic angle spinning (MAS) nuclear magnetic resonance (NMR) analysis of human gall bladder stones collected from patients suffering from malignant and benign gall bladder disease was carried out which revealed different polymorphs of cholesterol in these stones. All gall bladder stones in present study had cholesterol as their main constituent. (13)C CP-MAS NMR analysis revealed three forms of cholesterol molecules in these stones, which are anhydrous form, monohydrate crystalline with amorphous form and monohydrate crystalline form. Our study revealed that stones collected from patients associated with chronic cholecystitis (CC) disease have mostly different polymorph of cholesterol than stones collected from patients associated with gall bladder cancer (GBC). Such study will be helpful in understanding the mechanism of formation of gallstones which are associated with different gall bladder diseases. This is the first study by solid state NMR revealing different crystal polymorphism of cholesterol in human gallstones, extending the applicability of (13)C CP-MAS NMR technique for the routine study of gallstones.

  1. A Theoretical Design Approach for Passive Shimming of a Magic-Angle-Spinning NMR Magnet.

    PubMed

    Li, Frank X; Voccio, John P; Sammartino, Michael; Ahn, Minchul; Hahn, Seungyong; Bascuñán, Juan; Iwasa, Yukikazu

    2016-06-01

    This paper presents a passive shimming design approach for a magic-angle-spinning (MAS) NMR magnet. In order to achieve a 1.5-T magic-angle field in NMR samples, we created two independent orthogonal magnetic vector fields by two separate coils: the dipole and solenoid. These two coils create a combined 1.5-T magnetic field vector directed at the magic angle (54.74° from the spinning axis). Additionally, the stringent magnetic field homogeneity requirement of the MAS magnet is the same as that of a solenoidal NMR magnet. The challenge for the magic-angle passive shimming design is to correct both the dipole and solenoid magnetic field spherical harmonics with one set of iron pieces, the so-called ferromagnetic shimming. Furthermore, the magnetization of the iron pieces is produced by both the dipole and solenoid coils. In our design approach, a matrix of 2 mm by 5 mm iron pieces with different thicknesses was attached to a thin-walled tube, 90-mm diameter and 40-mm high. Two sets of spherical harmonic coefficients were calculated for both the dipole and solenoid coil windings. By using the multiple-objective linear programming optimization technique and coordinate transformations, we have designed a passive shimming set that can theoretically reduce 22 lower-order spherical harmonics and improve the homogeneity of our MAS NMR magnet.

  2. The HPV16 E7 Oncoprotein Disrupts Dendritic Cell Function and Induces the Systemic Expansion of CD11b+Gr1+ Cells in a Transgenic Mouse Model

    PubMed Central

    Damian-Morales, Gabriela; Serafín-Higuera, Nicolás; Moreno-Eutimio, Mario Adán; Cortés-Malagón, Enoc M.; Bonilla-Delgado, José; Rodríguez-Uribe, Genaro; Ocadiz-Delgado, Rodolfo; Lambert, Paul F.

    2016-01-01

    Objective. The aim of this study was to analyze the effects of the HPV16 E7 oncoprotein on dendritic cells (DCs) and CD11b+Gr1+ cells using the K14E7 transgenic mouse model. Materials and Methods. The morphology of DCs was analyzed in male mouse skin on epidermal sheets using immunofluorescence and confocal microscopy. Flow cytometry was used to determine the percentages of DCs and CD11b+Gr1+ cells in different tissues and to evaluate the migration of DCs. Results. In the K14E7 mouse model, the morphology of Langerhans cells and the migratory activity of dendritic cells were abnormal. An increase in CD11b+Gr1+ cells was observed in the blood and skin of K14E7 mice, and molecules related to CD11b+Gr1+ chemoattraction (MCP1 and S100A9) were upregulated. Conclusions. These data suggest that the HPV16 E7 oncoprotein impairs the function and morphology of DCs and induces the systemic accumulation of CD11b+Gr1+ cells. PMID:27478837

  3. Rac1 regulates skin tumors by regulation of keratin 17 through recruitment and interaction with CD11b+Gr1+ cells

    PubMed Central

    Zhou, Ying; Zhu, Shaojun; Liu, Juanjuan; Wang, Dong; Deng, Anmei; Wang, Zhipeng

    2014-01-01

    Rac1 is a member of the Rho family of small GTPases that control cells proliferation, differentiation, migration, and inflammation. Rac1 is crucial in tumorigenesis and development. Keratin17 and CD11b+Gr1+ cells are considered to regulate skin inflmmation. Here we discuss the regulation of Rac1 on skin tumor formation and its relationship. In samples from human skin squamous cell carcinoma (SCC), Rac1 activity was higher in cancer tissues than in normal skin and activity correlated with keratin 17 overexpression. In a DMBA/TPA-induced mouse skin tumor model, inhibition of Rac1 activity and depletion of CD11b+Gr1+ cells resulted in significant tumor formation. TPA induced recruitment of CD11b+Gr1+ cells into dermis; however, Rac1 inhibitor abolished this recruitment. In vitro, Rac1 induced interferon (IFN) and interlukin (IL6) production in keratinocytes, repression of keratin 17 inhibited IFN and IL6 production induced by Rac1. Moreover, both inhibition of Rac1 activity and repression of keratin 17 restricted proliferation and induction of differentiation in keratinocytes. Coculture of CD11b+Gr1+ cells with keratinocytes activated Wnt pathway in keratinocytes, resulting in enhanced Rac1 activity, overexpression of keratin 17, and hyperproliferation of keratinocytes. Our results suggested that hyperactive Rac1 recruited and interacted with CD11b+Gr1+ cells, inducing keratin 17-regulated inflammation and promoting skin tumor formation. PMID:24962779

  4. The effect of interleukin 17 and Toll-like receptor 2 on CD11b expression and apoptosis of neutrophils in zymosaninduced arthritis and paw oedema

    PubMed Central

    Milanova, Viktoriya; Ivanovska, Nina

    2014-01-01

    We investigated the effect of interleukin (IL)-17 on Ly6G+ cell apoptosis in zymosan-induced arthritis (ZIA) and oedema (ZIO). Zymosan injection at the ankle joint caused swelling and coincided with histological joint alterations and IL-17A expression in areas with cell infiltrates. Flow cytometry of blood demonstrated increased frequencies of Ly6G+CD11b+ cells and their decreased apoptosis in ZIA. Annexin V+ neutrophils had lower CD11b expression, unlike Annexin V− cells. Cell survival for 12 hours was affected neither by IL-17 nor by zymosan alone, while both stimuli diminished Annexin V+ cell frequencies and up-regulated CD11b on Annexin V− cells. Interleukin 17 antagonised to the effects of zymosan in 24-hour cultures. The administration of IL-17 in ZIO increased paw thickness, enlarged the blood Ly6G+ pool, elevated CD11b expression and decreased apoptosis. We suggest that altered neutrophil apoptosis in arthritis can be overcome by anti-IL-17 therapy combined with an inhibition of Toll-like receptor (TLR) 2 and CD11b signalling. PMID:26155114

  5. Highly Expression of CD11b and CD32 on Peripheral Blood Mononuclear Cells from Patients with Adult-Onset Still’s Disease

    PubMed Central

    Kim, Hyoun-Ah; Choi, Bunsoon; Suh, Chang-Hee; Han, Mi Hwa; Jung, Ju-Yang; Sayeed, Hasan M.; Kim, Ye Won; Sohn, Seonghyang

    2017-01-01

    Background: We investigated the potential role of several pattern-recognition receptors (PRRs; CD11b, CD11c, CD32, CD206, CD209, and dectin-1) in adult-onset Still’s disease (AOSD). Methods: The study included 13 untreated AOSD patients, 19 rheumatoid arthritis (RA) patients (as a disease control), and 19 healthy controls (HCs). The PRRs were quantified in peripheral blood using flow cytometry. The serum levels of interleukin-17 (IL-17), IL-18, and IL-23 were measured by enzyme-linked immunosorbent assay. Results: Significantly higher mean frequencies of cells presenting CD11b and CD32 from whole blood were observed in patients with AOSD than in patients with RA or HC. The levels of IL-17, IL-18, and IL-23 were elevated in AOSD patients compared to HCs. CD11b frequencies from whole cells correlated with systemic scores, lactate dehydrogenase (LDH) levels, aspartate transaminase levels, interleukin-23 (IL-23) levels, and IL-18. Frequencies of CD209 from granulocytes were significantly correlated with systemic scores, and the erythrocyte sedimentation rate and levels of C-reactive protein, ferritin, LDH, IL-23, and interleukin-18 (IL-18). Conclusions: Elevated frequencies of circulating CD11b-positive cells and positive correlations with disease activity markers suggest that circulating CD11b-positive cells contribute to the pathogenesis of AOSD. PMID:28106835

  6. FUNCTIONAL ROLES FOR THE STRIATAL-ENRICHED TRANSCRIPTION FACTOR, BCL11B, IN THE CONTROL OF STRIATAL GENE EXPRESSION AND TRANSCRIPTIONAL DYSREGULATION IN HUNTINGTON'S DISEASE

    PubMed Central

    Desplats, Paula A.; Lambert, James R.; Thomas, Elizabeth A.

    2008-01-01

    Transcriptional dysregulation has emerged as a central pathogenic mechanism in Huntington's disease (HD), which is associated with neuropathological changes predominantly in the striatum. Here we demonstrate that expression of Bcl11b (a.k.a. CTIP2), a transcription factor exhibiting highly-enriched localization in adult striatum, is significantly decreased in HD cells, mouse models and human subjects and that overexpression of Bcl11b attenuates toxic effects of mutant huntingtin in cultured striatal neurons. We show that Bcl11b directly activates the proximal promoter regions of striatal-enriched genes and can increase mRNA levels of striatal-expressing genes. We further demonstrate an interaction between Bcl11b and huntingtin protein in cultured cells and brain homogenates from HD R6/1 and YAC72 transgenic mice. We propose that sequestration and/or decreased expression of Bcl11b in HD is responsible, at least in part, for the dysregulation of striatal gene expression observed in HD and may contribute to the specificity of pathology observed in this disease. PMID:18595722

  7. On the implementation of a chain nuclear reaction of thermonuclear fusion on the basis of the p+{sup 11}B process

    SciTech Connect

    Belyaev, V. S.; Krainov, V. P.; Zagreev, B. V.; Matafonov, A. P.

    2015-07-15

    Various theoretical and experimental schemes for implementing a thermonuclear reactor on the basis of the p+{sup 11}B reaction are considered. They include beam collisions, fusion in degenerate plasmas, ignition upon plasma acceleration by ponderomotive forces, and the irradiation of a solid-state target from {sup 11}B with a proton beam under conditions of a Coulomb explosion of hydrogen microdrops. The possibility of employing ultra-short high-intensity laser pulses to initiate the p+{sup 11}B reaction under conditions far from thermodynamic equilibrium is discussed. This and some other weakly radioactive thermonuclear reactions are promising owing to their ecological cleanness—there are virtually no neutrons among fusion products. Nuclear reactions that follow the p+{sup 11}B reaction may generate high-energy protons, sustaining a chain reaction, and this is an advantage of the p+{sup 11}B option. The approach used also makes it possible to study nuclear reactions under conditions close to those in the early Universe or in the interior of stars.

  8. Milli-Arcsecond (MAS) Imaging of the Solar Corona

    NASA Astrophysics Data System (ADS)

    Davila, Joseph M.; Oktem, Figen S.; Kamalabadi, Farzad; O'Neill, John; Novo-Gradac, Anne-Marie; Daw, Adrian N.; Rabin, Douglas M.

    2016-05-01

    Dissipation in the solar corona is believed to occur in extremely thin current sheets of order 1-100 km. Emission from these hot but thin current sheets should be visible in coronal EUV emission lines. However, this spatial scale is far below the resolution of existing imaging instruments, so these dissipation sites have never been observed individually. Conventional optics cannot be manufactured with sufficient surface figure accuracy to obtain the required spatial resolution in the extreme-ultraviolet where these hot plasmas radiate. A photon sieve, a diffractive imaging element similar to a Fresnel zone plate, can be manufactured to provide a few milli-arcsec (MAS) resolution, with much more readily achievable tolerances than with conventional imaging technology. Prototype photon sieve elements have been fabricated and tested in the laboratory. A full-scale ultra-high resolution instrument will require formation flying and computational image deconvolution. Significant progress has been made in overcoming these challenges, and some recent results in these areas are discussed. A simple design for a sounding rocket concept demonstration payload is presented that obtains 80 MAS (0.080 arcsec) imaging with a 100 mm diameter photon sieve to image Fe XIV 334 and Fe XVI 335. These images will show the structure of the corona at a resolution never before obtained, and they will also allow a study of the temperature structure in the dissipation region.

  9. A combined deuterium NMR and quantum chemical investigation of inequivalent hydrogen bonds in organic solids.

    PubMed

    Webber, Renee; Penner, Glenn H

    2012-01-01

    Deuterium magic angle spinning (MAS) NMR spectroscopy and quantum chemical calculations are used to investigate organic solids in which inequivalent hydrogen bonds are present. The use of (2)H MAS allows one to measure the chemical shift, δ, quadrupolar coupling constant, C(Q), and asymmetry in the quadrupolar interaction, η(Q), for each type of hydrogen bond present in the system. Quantum chemical calculations of the magnetic shielding (σ, which can be related to δ) and the electric field gradient (EFG, which can be related to C(Q)) are compared to the experimental results and are discussed with respect to the relative strengths of the hydrogen bonds within each system.

  10. A Bayesian Atmospheric Retrieval Performed on HAT-P-16b and WASP-11b/HAT-P-10b

    NASA Astrophysics Data System (ADS)

    McIntyre, Kathleen J.; Harrington, Joseph; Challener, Ryan C.; Hardin, Matthew Ryan; Bowman, Oliver Oliver; Foster, Andrew S. D.; Lenius, Maria; Hartman, Joel D.; Bakos, Gaspar; Blecic, Jasmina; Cubillos, Patricio; Ariston Hardy, Ryan; Cameron, Andrew

    2016-10-01

    HAT-P-16b is a hot (equilibrium temperature 1626 ± 40 K, assuming zero Bond albedo and efficient energy redistribution), 4.19 ± 0.09 Jupiter-mass exoplanet orbiting an F8 star every 2.775960 ± 0.000003 days (Buchhave et al 2010). WASP-11b/HAT-P-10b is a cooler (1020 ± 17 K), 0.487 ± 0.018 Jupiter-mass exoplanet orbiting a K3 star every 3.7224747 ± 0.0000065 days (Bakos et al. 2009, co-discovered by West et al. 2008). We observed secondary eclipses of both planets using the 3.6 μm and 4.5 μm channels of the Spitzer Space Telescope's Infrared Array Camera (program ID 60003). We applied our Bayesian Atmospheric Radiative Transfer (BART) code to constrain the temperature-pressure profiles and atmospheric molecular abundances of the two planets. Spitzer is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. This work was supported by NASA Planetary Atmospheres grant NNX12AI69G and NASA Astrophysics Data Analysis Program grant NNX13AF38G.

  11. Highly-focused boron implantation in diamond and imaging using the nuclear reaction 11B(p, α)8Be

    NASA Astrophysics Data System (ADS)

    Ynsa, M. D.; Ramos, M. A.; Skukan, N.; Torres-Costa, V.; Jakšić, M.

    2015-04-01

    Diamond is an especially attractive material because of its gemological value as well as its unique mechanical, chemical and physical properties. One of these properties is that boron-doped diamond is an electrically p-type semiconducting material at practically any boron concentration. This property makes it possible to use diamonds for multiple industrial and technological applications. Boron can be incorporated into pure diamond by different techniques including ion implantation. Although typical energies used to dope diamond by ion implantation are about 100 keV, implantations have also been performed with energies above MeV. In this work CMAM microbeam setup has been used to demonstrate capability to implant boron with high energies. An 8 MeV boron beam with a size of about 5 × 3 μm2 and a beam current higher than 500 pA has been employed while controlling the beam position and fluence at all irradiated areas. The subsequent mapping of the implanted boron in diamond has been obtained using the strong and broad nuclear reaction 11B(p, α)8Be at Ep = 660 keV. This reaction has a high Q-value (8.59 MeV for α0 and 5.68 MeV for α1) and thus is almost interference-free. The sensitivity of the technique is studied in this work.

  12. A programmable baseband chain for a WCDMA/WLAN (802.11b) multi-standard zero-IF receiver

    NASA Astrophysics Data System (ADS)

    Rodriguez de Llera Gonzalez, Delia; Ismail, Mohammed

    2005-06-01

    As we move towards convergent 4G Wireless encompassing both 3G cellular (WCDMA) for wide area networks and Wireless LAN for "hot-spots", the development of low power, low cost multi-band multi-standard wireless chipset solutions is a must. To this end this paper presents a programmable architecture for an analog baseband chain intended for use in a zero-IF multi-standard WCDMA/WLAN(802.11b) radio receiver. It also addresses the DC offset cancellation in the baseband chain. This is one of the major impairments in zero-IF receivers whose simplicity makes them suitable for single-chip multi-standard designs but where DC offset can reduce the receiver performance if a proper DC offset cancellation scheme is not devised. System level design of the baseband chain is given leading to design specifications of the different blocks in the chain. Extensive simulations carried out in MATLAB/SimuLink at the system level and in Cadence design tools at the circuit level show the performance of the system. The circuits will be fabricated in a 0.18μm CMOS process for a 1.8 V power supply.

  13. A hookworm glycoprotein that inhibits neutrophil function is a ligand of the integrin CD11b/CD18.

    PubMed

    Moyle, M; Foster, D L; McGrath, D E; Brown, S M; Laroche, Y; De Meutter, J; Stanssens, P; Bogowitz, C A; Fried, V A; Ely, J A

    1994-04-01

    The chronic survival of many endoparasites is dependent on the ability of these organisms to escape the host immune response. Identification of the molecular mechanisms by which these organisms evade this response may yield novel approaches in the development of anti-inflammatory agents. We describe here the discovery and characterization of a novel 41-kilodalton glycoprotein from the canine hookwork (Ancylostoma caninum) that potently inhibits CD11/CD18-dependent neutrophil function in vitro. Neutrophil inhibitory factor (NIF) blocks the adhesion of activated human neutrophils to vascular endothelial cells as well as the release of H2O2 from activated neutrophils, over a similar concentration range (IC50 10-20 nM). Studies aimed at determining the nature of the NIF binding site on neutrophils revealed selective, high affinity binding of this protein to the integrin CD11b/CD18. A cDNA encoding NIF was isolated from a canine hookworm cDNA library. NIF comprises a mature polypeptide of 257 amino acids, preceded by a 17-amino acid leader. The mature protein has 10 cysteines and has seven potential N-linked glycosylation sites. NIF has no significant sequence homologies to any previously reported protein. As such, NIF represents a prototype of a novel class of leukocyte function inhibitors.

  14. Optimizing Adiabaticity in NMR

    NASA Astrophysics Data System (ADS)

    Vandermause, Jonathan; Ramanathan, Chandrasekhar

    We demonstrate the utility of Berry's superadiabatic formalism for numerically finding control sequences that implement quasi-adiabatic unitary transformations. Using an iterative interaction picture, we design a shortcut to adiabaticity that reduces the time required to perform an adiabatic inversion pulse in liquid state NMR. We also show that it is possible to extend our scheme to two or more qubits to find adiabatic quantum transformations that are allowed by the control algebra, and demonstrate a two-qubit entangling operation in liquid state NMR. We examine the pulse lengths at which the fidelity of these adiabatic transitions break down and compare with the quantum speed limit.

  15. 31P Solid State NMR Studies of ZrP, Mg3P2, and CdPS3

    DTIC Science & Technology

    1988-01-01

    valence , in contrast to that in ZrP, Mg3P2, and MgP4. The 3 1 p solid state NMR spectra are shown in Figure 9. The MAS spectrum reveals a single...orange crystals were recovered from hot concentrated HCa . In one experi- RESULTS AND DISCUSSION ment, brilliant black polyhedral crystals of ZnSnP, were

  16. CD103+CD11b+ Dendritic Cells Induce Th17 T Cells in Muc2-Deficient Mice with Extensively Spread Colitis

    PubMed Central

    Wenzel, Ulf A.; Jonstrand, Caroline; Hansson, Gunnar C.; Wick, Mary Jo

    2015-01-01

    Mucus alterations are a feature of ulcerative colitis (UC) and can drive inflammation by compromising the mucosal barrier to luminal bacteria. The exact pathogenesis of UC remains unclear, but CD4+ T cells reacting to commensal antigens appear to contribute to pathology. Given the unique capacity of dendritic cells (DCs) to activate naive T cells, colon DCs may activate pathogenic T cells and contribute to disease. Using Muc2-/- mice, which lack a functional mucus barrier and develop spontaneous colitis, we show that colitic animals have reduced colon CD103+CD11b- DCs and increased CD103-CD11b+ phagocytes. Moreover, changes in colonic DC subsets and distinct cytokine patterns distinguish mice with distally localized colitis from mice with colitis spread proximally. Specifically, mice with proximally spread, but not distally contained, colitis have increased IL-1β, IL-6, IL-17, TNFα, and IFNγ combined with decreased IL-10 in the distal colon. These individuals also have increased numbers of CD103+CD11b+ DCs in the distal colon. CD103+CD11b+ DCs isolated from colitic but not noncolitic mice induced robust differentiation of Th17 cells but not Th1 cells ex vivo. In contrast, CD103-CD11b+ DCs from colitic Muc2-/- mice induced Th17 as well as Th1 differentiation. Thus, the local environment influences the capacity of intestinal DC subsets to induce T cell proliferation and differentiation, with CD103+CD11b+ DCs inducing IL-17-producing T cells being a key feature of extensively spread colitis. PMID:26121642

  17. Enhanced expression of PD-L1 in oral squamous cell carcinoma-derived CD11b(+)Gr-1(+) cells and its contribution to immunosuppressive activity.

    PubMed

    Fuse, Hiroki; Tomihara, Kei; Heshiki, Wataru; Yamazaki, Manabu; Akyu-Takei, Rie; Tachinami, Hidetake; Furukawa, Ken-Ichiro; Sakurai, Kotaro; Rouwan, Moniruzzaman; Noguchi, Makoto

    2016-08-01

    Cancer is often associated with dysregulation of both the humoral and cellular immune response, which in some instances is believed to result from changes in immune cell populations. For example, immunosuppressive CD11b(+)Gr-1(+) myeloid-derived suppressor cells have been shown to proliferate in the tumor microenvironment and surrounding tissues, highlighting the relationship between tumor growth and impairment of the immune response. However, the role of myeloid-derived suppressor cells in cancer progression has not been fully characterized because these cells are heterogeneous with properties influenced by the type and location of the tumor. Here, we show that CD11b(+)Gr-1(+) cells are elevated in the peripheral blood, spleen, and tumor of mice with oral squamous cell carcinoma. The phenotype and function of these cells varied depending on the tissue of origin. In particular, CD11b(+)Gr-1(+) cells in tumors expressed PD-L1 more abundantly than those in other tissues. Accordingly, CD11b(+)Gr-1(+) cells from tumors, but not from the spleen, suppressed T cell proliferation in vitro. The results suggest that tumor-derived or immune factors result in the accumulation of phenotypically and functionally diverse populations of CD11b(+)Gr-1(+) cells in mice with oral squamous cell carcinoma. The data also indicate that PD-L1 expression in CD11b(+)Gr-1(+) cells contributes to immune suppression, implying that targeting both myeloid-derived suppressor cells and PD-L1 would be an effective immunotherapeutic strategy against oral cancer.

  18. T Cell–Derived Granulocyte-Macrophage Colony-Stimulating Factor Contributes to Dry Eye Disease Pathogenesis by Promoting CD11b+ Myeloid Cell Maturation and Migration

    PubMed Central

    Dohlman, Thomas H.; Ding, Julia; Dana, Reza; Chauhan, Sunil K.

    2017-01-01

    Purpose Growing evidence suggests that granulocyte-macrophage colony-stimulating factor (GM-CSF) contributes to T helper 17 (Th17) cell–associated immunoinflammatory diseases. The purpose of this study was to evaluate the effect of T cell–derived GM-CSF on CD11b+ myeloid cell function in dry eye disease (DED). Methods In a murine model of DED, quantitative real-time PCR and ELISA were used to measure GM-CSF expression at the ocular surface, and flow cytometry was used to enumerate GM-CSF producing Th17 cells. A granulocyte-macrophage colony-stimulating factor neutralizing antibody was used topically in vivo and in an in vitro culture system to evaluate the role of GM-CSF in recruiting and maturing CD11b+ cells. Clinical disease severity was evaluated after topical administration of GM-CSF neutralizing antibody. Results In dry eye disease, GM-CSF is significantly upregulated at the ocular surface and the frequency of GM-CSF producing Th17 cells is significantly increased in the draining lymph nodes. In vitro neutralization of GM-CSF from CD4+ T cells derived from DED mice suppresses major histocompatibility complex II expression by CD11b+ cells and CD11b+ cell migration. Topical neutralization of GM-CSF in a murine model of DED suppresses CD11b+ maturation and migration, as well as Th17 cell induction, yielding a reduction in clinical signs of disease. Conclusions T helper 17 cell–derived GM-CSF contributes to DED pathogenesis by promoting CD11b+ cell activation and migration to the ocular surface. PMID:28241321

  19. CD103+ lung dendritic cells (LDCs) induce stronger Th1/Th17 immunity to a bacterial lung infection than CD11b(hi) LDCs.

    PubMed

    Shekhar, Sudhanshu; Peng, Ying; Wang, Shuhe; Yang, Xi

    2017-02-13

    Recent studies suggest differential roles for CD103+ and CD11b(hi) lung dendritic cells (LDCs) in host defense against viral and bacterial infections. In this study, we examined the contribution of these LDC subsets in protective immunity to chlamydial lung infection using a Chlamydia muridarum mouse infection model. We found that CD103+ LDCs showed higher expression of costimulatory molecules (CD40, CD80 and CD86) and increased production of cytokines (IL-12p70, IL-10, IL-23 and IL-6) compared with CD11b(hi) LDCs, but the expression of programmed death-ligand 1 (PD-L1) was similar between the two subsets. More importantly, we found, in adoptive transfer experiments, that the mice receiving CD103+ LDCs from Chlamydia-infected mice exhibited better protection than the recipients of CD11b(hi) LDCs, which was associated with more robust Th1/Th17 cytokine responses. In addition, in vitro experiments showed that CD103+ LDCs induced stronger IFN-γ and IL-17 responses, when cocutured with chlamydial antigen-primed CD4+ T cells, than CD11b(hi) LDCs. Furthermore, the blockade of PD1 in the culture of CD4+ T cells with either CD103+ or CD11b(hi) LDCs enhanced production of IFN-γ and IL-17. In conclusion, our data provide direct evidence that CD103+ LDCs are more potent in promoting Th1/Th17 immunity to chlamydial lung infection than CD11b(hi) LDCs.Cellular & Molecular Immunology advance online publication, 13 February 2017; doi:10.1038/cmi.2016.68.

  20. Association of Aldosterone Synthase Polymorphism (CYP11B2 -344T>C) and Genetic Ancestry with Atrial Fibrillation and Serum Aldosterone in African Americans with Heart Failure

    PubMed Central

    Bress, Adam; Han, Jin; Patel, Shitalben R.; Desai, Ankit A.; Mansour, Ibrahim; Groo, Vicki; Progar, Kristin; Shah, Ebony; Stamos, Thomas D.; Wing, Coady; Garcia, Joe G. N.; Kittles, Rick; Cavallari, Larisa H.

    2013-01-01

    The objective of this study was to examine the extent to which aldosterone synthase genotype (CYP11B2) and genetic ancestry correlate with atrial fibrillation (AF) and serum aldosterone in African Americans with heart failure. Clinical data, echocardiographic measurements, and a genetic sample for determination of CYP11B2 -344T>C (rs1799998) genotype and genetic ancestry were collected from 194 self-reported African Americans with chronic, ambulatory heart failure. Genetic ancestry was determined using 105 autosomal ancestry informative markers. In a sub-set of patients (n = 126), serum was also collected for determination of circulating aldosterone. The CYP11B2 −344C allele frequency was 18% among the study population, and 19% of patients had AF. Multiple logistic regression revealed that the CYP11B2 −344CC genotype was a significant independent predictor of AF (OR 12.7, 95% CI 1.60–98.4, p = 0.0150, empirical p = 0.011) while holding multiple clinical factors, left atrial size, and percent European ancestry constant. Serum aldosterone was significantly higher among patients with AF (p = 0.036), whereas increased West African ancestry was inversely correlated with serum aldosterone (r = −0.19, p = 0.037). The CYP11B2 −344CC genotype was also overrepresented among patients with extreme aldosterone elevation (≥90th percentile, p = 0.0145). In this cohort of African Americans with chronic ambulatory heart failure, the CYP11B2 −344T>C genotype was a significant independent predictor of AF while holding clinical, echocardiographic predictors, and genetic ancestry constant. In addition, increased West African ancestry was associated with decreased serum aldosterone levels, potentially providing an explanation for the lower risk for AF observed among African Americans. PMID:23936266

  1. Expansion of CD11b(+)Ly6G (+)Ly6C (int) cells driven by medroxyprogesterone acetate in mice bearing breast tumors restrains NK cell effector functions.

    PubMed

    Spallanzani, Raúl Germán; Dalotto-Moreno, Tomás; Raffo Iraolagoitia, Ximena Lucía; Ziblat, Andrea; Domaica, Carolina Inés; Avila, Damián Ezequiel; Rossi, Lucas Ezequiel; Fuertes, Mercedes Beatriz; Battistone, María Agustina; Rabinovich, Gabriel Adrián; Salatino, Mariana; Zwirner, Norberto Walter

    2013-12-01

    The progesterone analog medroxyprogesterone acetate (MPA) is widely used as a hormone replacement therapy in postmenopausal women and as contraceptive. However, prolonged administration of MPA is associated with increased incidence of breast cancer through ill-defined mechanisms. Here, we explored whether exposure to MPA during mammary tumor growth affects myeloid-derived suppressor cells (MDSCs; CD11b(+)Gr-1(+), mostly CD11b(+)Ly6G(+)Ly6C(int) and CD11b(+)Ly6G(-)Ly6C(high) cells) and natural killer (NK) cells, potentially restraining tumor immunosurveillance. We used the highly metastatic 4T1 breast tumor (which does not express the classical progesterone receptor and expands MDSCs) to challenge BALB/c mice in the absence or in the presence of MPA. We observed that MPA promoted the accumulation of NK cells in spleens of tumor-bearing mice, but with reduced degranulation ability and in vivo cytotoxic activity. Simultaneously, MPA induced a preferential expansion of CD11b(+)Ly6G(+)Ly6C(int) cells in spleen and bone marrow of 4T1 tumor-bearing mice. In vitro, MPA promoted nuclear mobilization of the glucocorticoid receptor (GR) in 4T1 cells and endowed these cells with the ability to promote a preferential differentiation of bone marrow cells into CD11b(+)Ly6G(+)Ly6C(int) cells that displayed suppressive activity on NK cell degranulation. Sorted CD11b(+)Gr-1(+) cells from MPA-treated tumor-bearing mice exhibited higher suppressive activity on NK cell degranulation than CD11b(+)Gr-1(+) cells from vehicle-treated tumor-bearing mice. Thus, MPA, acting through the GR, endows tumor cells with an enhanced capacity to expand CD11b(+)Ly6G(+)Ly6C(int) cells that subsequently display a stronger suppression of NK cell-mediated anti-tumor immunity. Our results describe an alternative mechanism by which MPA may affect immunosurveillance and have potential implication in breast cancer incidence.

  2. [Implementation of paragraph 11b of the German Animal Welfare Act on the basis of the so-called "Quality Breeding" Report].

    PubMed

    Schmitz, J

    2004-03-01

    Enforcement of paragraph 11b of the German Animal Welfare Act is a responsibility of breeders and their organisations as well as executive local authorities. The Report on Defective Breeds of the Federal Ministry of Agriculture describes numerous breeding traits which are in conflict with animal welfare and gives valuable information for fancy or pet breeding. Yet a selection has to be made for taking legal actions, following specific criteria. With four examples different cases are presented, each requiring a different approach by the veterinarian authorities. Court decisions in Hessen concerning bans on breeding white cats and crested ducks show that the paragraph 11b is executable.

  3. Characterization of a novel monoclonal antibody with restricted specificity to the free beta 2 integrin alpha M CD11b subunit.

    PubMed

    Tanfous, Naouel Guedel-Ben; Essafi, Makram; Larguech, Beya; Barbouche, Ridha; Fathallah, Dahmani M

    2007-12-01

    Leukocyte cell surface expression and function of beta2 integrins require the intracellular association of alpha subunits, CD11a, b, c, d, respectively, with the common CD18 beta2 subunit. We have raised and characterized a murine MAb -- ME-MDF -- directed against the low affinity form of the human integrin alphaM subunit CD11b A-domain. MAb ME-MDF is an IgG2a that has a kDa of 2,45461 +/- 0.12 x 10(-9) M. MAb ME-MDF recognizes both the low and high affinity forms of the CD11b A-domain. Flow cytometry showed that ME-MDF does not recognize the heterodimeric CD11b/CD18 molecule at the surface of polymorphonuclear cells and the human monoblast cell line U937. Western blot analysis of U937 cell line cell surface proteins demonstrated that ME-MDF reacts specifically with the CD11b subunit but does not react with the heterodimeric CD11b/CD18 complex, a feature that differentiates it from other CD11b A-dom-specific MAbs. These observations suggest that ME-MDF recognizes an epitope that is involved in the association of the two subunits and hence is not accessible within the heterodimeric form of the CD11b/CD18 molecule. These data show that the CD11b A-dom engages not only the MIDAS but also the ME-MDF-specific epitope to associate with the CD18 subunit. We have also constructed, and expressed in the yeast Pichia pastoris, the corresponding recombinant scFv form of MAb ME-MDF and characterized the CDRs. MAb ME-MDF is characterized by short VH and VL CDR3. MAb ME-MDF and/or its recombinant scFv form would be very useful to study the structural basis of the association between the alpha and beta2 integrin subunits and to investigate the possibility of modulating CR3 cell surface expression by preventing subunit association.

  4. Solid state NMR studies of gels derived from low molecular mass gelators.

    PubMed

    Nonappa; Kolehmainen, E

    2016-07-13

    Since its invention more than six decades ago, nuclear magnetic resonance (NMR) spectroscopy has evolved as an inevitable part of chemical as well as structural analysis of small molecules, polymers, biomaterials and hybrid materials. In the solution state, due to the increased viscosity of complex viscoelastic fluids such as gels, liquid crystals and other soft materials, the rate of molecular tumbling is reduced, which in turn affects the chemical shift anisotropy, dipolar and quadrupolar interactions. As a consequence the solution state NMR spectra show broad lines, and therefore, extracting detailed structural information is a challenging task. In this context, solid state (SS) NMR has the ability to distinguish between a minute amount of polymorphic forms, conformational changes, and the number of non-equivalent molecules in an asymmetric unit of a crystal lattice, and to provide both qualitative as well as quantitative analytical data with a short-range order. Therefore, SS NMR has continued to evolve as an indispensable tool for structural analysis and gave birth to a new field called NMR crystallography. Solid state cross polarization (CP) and high resolution (HR) magic angle spinning (MAS) NMR spectroscopy has been used to study weak interactions in polymer gels. However, the application of SS NMR spectroscopy to study gels derived from low molecular weight gelators has been limited until recently. In this review, we will focus on the importance of solid state NMR spectroscopy in understanding and elucidating the structure of supramolecular gels derived from low molecular weight gelators with selected examples.

  5. Solid state NMR studies of gels derived from low molecular mass gelators

    PubMed Central

    Kolehmainen, E.

    2016-01-01

    Since its invention more than six decades ago, nuclear magnetic resonance (NMR) spectroscopy has evolved as an inevitable part of chemical as well as structural analysis of small molecules, polymers, biomaterials and hybrid materials. In the solution state, due to the increased viscosity of complex viscoelastic fluids such as gels, liquid crystals and other soft materials, the rate of molecular tumbling is reduced, which in turn affects the chemical shift anisotropy, dipolar and quadrupolar interactions. As a consequence the solution state NMR spectra show broad lines, and therefore, extracting detailed structural information is a challenging task. In this context, solid state (SS) NMR has the ability to distinguish between a minute amount of polymorphic forms, conformational changes, and the number of non-equivalent molecules in an asymmetric unit of a crystal lattice, and to provide both qualitative as well as quantitative analytical data with a short-range order. Therefore, SS NMR has continued to evolve as an indispensable tool for structural analysis and gave birth to a new field called NMR crystallography. Solid state cross polarization (CP) and high resolution (HR) magic angle spinning (MAS) NMR spectroscopy has been used to study weak interactions in polymer gels. However, the application of SS NMR spectroscopy to study gels derived from low molecular weight gelators has been limited until recently. In this review, we will focus on the importance of solid state NMR spectroscopy in understanding and elucidating the structure of supramolecular gels derived from low molecular weight gelators with selected examples. PMID:27374054

  6. Modern NMR Spectroscopy.

    ERIC Educational Resources Information Center

    Jelinski, Lynn W.

    1984-01-01

    Discusses direct chemical information that can be obtained from modern nuclear magnetic resonance (NMR) methods, concentrating on the types of problems that can be solved. Shows how selected methods provide information about polymers, bipolymers, biochemistry, small organic molecules, inorganic compounds, and compounds oriented in a magnetic…

  7. Autonomous driving in NMR.

    PubMed

    Perez, Manuel

    2017-01-01

    The automatic analysis of NMR data has been a much-desired endeavour for the last six decades, as it is the case with any other analytical technique. This need for automation has only grown as advances in hardware; pulse sequences and automation have opened new research areas to NMR and increased the throughput of data. Full automatic analysis is a worthy, albeit hard, challenge, but in a world of artificial intelligence, instant communication and big data, it seems that this particular fight is happening with only one technique at a time (let this be NMR, MS, IR, UV or any other), when the reality of most laboratories is that there are several types of analytical instrumentation present. Data aggregation, verification and elucidation by using complementary techniques (e.g. MS and NMR) is a desirable outcome to pursue, although a time-consuming one if performed manually; hence, the use of automation to perform the heavy lifting for users is required to make the approach attractive for scientists. Many of the decisions and workflows that could be implemented under automation will depend on the two-way communication with databases that understand analytical data, because it is desirable not only to query these databases but also to grow them in as much of an automatic manner as possible. How these databases are designed, set up and the data inside classified will determine what workflows can be implemented. Copyright © 2016 John Wiley & Sons, Ltd.

  8. MAS C-Terminal Tail Interacting Proteins Identified by Mass Spectrometry- Based Proteomic Approach

    PubMed Central

    Tirupula, Kalyan C.; Zhang, Dongmei; Osbourne, Appledene; Chatterjee, Arunachal; Desnoyer, Russ; Willard, Belinda; Karnik, Sadashiva S.

    2015-01-01

    Propagation of signals from G protein-coupled receptors (GPCRs) in cells is primarily mediated by protein-protein interactions. MAS is a GPCR that was initially discovered as an oncogene and is now known to play an important role in cardiovascular physiology. Current literature suggests that MAS interacts with common heterotrimeric G-proteins, but MAS interaction with proteins which might mediate G protein-independent or atypical signaling is unknown. In this study we hypothesized that MAS C-terminal tail (Ct) is a major determinant of receptor-scaffold protein interactions mediating MAS signaling. Mass-spectrometry based proteomic analysis was used to comprehensively identify the proteins that interact with MAS Ct comprising the PDZ-binding motif (PDZ-BM). We identified both PDZ and non-PDZ proteins from human embryonic kidney cell line, mouse atrial cardiomyocyte cell line and human heart tissue to interact specifically with MAS Ct. For the first time our study provides a panel of PDZ and other proteins that potentially interact with MAS with high significance. A ‘cardiac-specific finger print’ of MAS interacting PDZ proteins was identified which includes DLG1, MAGI1 and SNTA. Cell based experiments with wild-type and mutant MAS lacking the PDZ-BM validated MAS interaction with PDZ proteins DLG1 and TJP2. Bioinformatics analysis suggested well-known multi-protein scaffold complexes involved in nitric oxide signaling (NOS), cell-cell signaling of neuromuscular junctions, synapses and epithelial cells. Majority of these protein hits were predicted to be part of disease categories comprising cancers and malignant tumors. We propose a ‘MAS-signalosome’ model to stimulate further research in understanding the molecular mechanism of MAS function. Identifying hierarchy of interactions of ‘signalosome’ components with MAS will be a necessary step in future to fully understand the physiological and pathological functions of this enigmatic receptor. PMID

  9. MODIS Airborne simulator (MAS) Final Report for CLASIC

    SciTech Connect

    Thomas Arnold; Steven Platnick

    2010-11-24

    The MAS was flown aboard the NASA ER-2 for the CLASIC field experiment, and for all data collected, provided calibrated and geolocated (Level-1B) radiance data for it’s 50 spectral bands (ranging in wavelength for 0.47 to 14.3 µm). From the Level-1B data, as directed in the Statement of Work, higher order (Level-2) data products were derived. The Level-2 products include: a) cloud optical thickness, b) cloud effective radius, c) cloud top height (temperature), d) cloud fraction, e) cloud phase products. Preliminary Level-1B and Level-2 products were provided during the field experiment (typically within one or two days of data collection). Final version data products were made available in December 2008 following considerable calibration analysis. Data collection, data processing (to Level-2), and discussion of the calibration work are summarized below.

  10. H-1 Relaxation Times of Metabolites in Biological Samples Obtained with Nondestructive Ex-vivo Slow-MAS NMR

    SciTech Connect

    Hu, Jian Zhi; Wind, Robert A.; Rommereim, Donald N.

    2006-03-01

    Methods suitable for measuring 1H relaxation times such as T1, T2 and T1p, in small sized biological objects including live cells, excised organs and tissues, oil seeds etc., were developed in this work. This was achieved by combining inversion-recovery, spin-echo, or spin lock segment with the phase-adjusted spinning sideband (PASS) technique that was applied at slow sample spinning rate. Here, 2D-PASS was used to produce a high-resolution 1H spectrum free from the magnetic susceptibility broadening so that the relaxation parameters of individual metabolite can be determined. Because of the slow spinning employed, tissue and cell damage due to sample spinning is minimized. The methodologies were demonstrated by measuring 1H T1, T2 and T1p of metabolites in excised rat livers and sesame seeds at spinning rates of as low as 40 Hz.

  11. Generation and characterization of alkali metal clusters in Y-FAU zeolites. An ESR and MAS NMR spectroscopic study

    NASA Astrophysics Data System (ADS)

    Hannus, István; Béres, Attila; Nagy, János B.; Halász, János; Kiricsi, Imre

    1997-06-01

    Charged and neutral metal clusters of various compositions and sizes can be prepared by controlling the alkali metal content by the decomposition of alkali azides and the composition of the host zeolite by ion-exchange. ESR signals show that electron transfer from alkali metal atoms to alkali metal cations does occur, but in a direction opposite to that predicted by the gas-phase thermochemistry. Alkali metal clusters proved to be very active basic catalytic centers.

  12. Dual-band selective double cross polarization for heteronuclear polarization transfer between dilute spins in solid-state MAS NMR

    NASA Astrophysics Data System (ADS)

    Zhang, Zhengfeng; Miao, Yimin; Liu, Xiaoli; Yang, Jun; Li, Conggang; Deng, Feng; Fu, Riqiang

    2012-04-01

    A sinusoidal modulation scheme is described for selective heteronuclear polarization transfer between two dilute spins in double cross polarization magic-angle-spinning nuclear magnetic resonance spectroscopy. During the second N → C cross polarization, the 13C RF amplitude is modulated sinusoidally while the 15N RF amplitude is tangent. This modulation induces an effective spin-lock field in two selective frequency bands in either side of the 13C RF carrier frequency, allowing for simultaneous polarization transfers from 15N to 13C in those two selective frequency bands. It is shown by experiments and simulations that this sinusoidal modulation allows one to selectively polarize from 15N to its covalently bonded 13Cα and 13C' carbons in neighboring peptide planes simultaneously, which is useful for establishing the backbone connectivity between two sequential residues in protein structural elucidation. The selectivity and efficiency were experimentally demonstrated on a uniformly 13C,15N-labeled β1 immunoglobulin binding domain of protein G (GB1).

  13. Chemical shift tensor determination using magnetically oriented microcrystal array (MOMA): 13C solid-state CP NMR without MAS

    NASA Astrophysics Data System (ADS)

    Kusumi, R.; Kimura, F.; Song, G.; Kimura, T.

    2012-10-01

    Chemical shift tensors for the carboxyl and methyl carbons of L-alanine crystals were determined using a magnetically oriented microcrystal array (MOMA) prepared from a microcrystalline powder sample of L-alanine. A MOMA is a single-crystal-like composite in which microcrystals are aligned three-dimensionally in a matrix resin. The single-crystal rotation method was applied to the MOMA to determine the principal values and axes of the chemical shift tensors. The result showed good agreement with the literature data for the single crystal of L-alanine. This demonstrates that the present technique is a powerful tool for determining the chemical shift tensor of a crystal from a microcrystal powder sample.

  14. CD45/CD11b Positive Subsets of Adult Lung Anchorage-Independent Cells Harness Epithelial Stem Cells

    PubMed Central

    Peter, Yakov; Sen, Namita; Levantini, Elena; Keller, Steven; Ingenito, Edward P; Ciner, Aaron; Sackstein, Robert; Shapiro, Steven D

    2015-01-01

    Compensatory growth is mediated by multiple cell types that interact during organ repair. To elucidate the relationship between the stem/progenitor cells that proliferate or differentiate and the somatic cells of lung, we utilized a novel ex vivo pneumoexplant system. Applying this technique, we identified a sustained culture of repopulating adult progenitors in the form of free floating anchorage-independent cells (AICs). AICs did not express integrin proteins α5, β3, and β7, and constituted 37% of the total culture at day 14, yielding a mixed yet conserved population that recapitulated RNA expression patterns of the healthy lung. AICs exhibited rapid proliferation manifested by a marked 60-fold increase in cell numbers by day 21. Over 50% of the AIC population was cKit+ or double-positive for CD45+ and CD11b+ antigenic determinants, consistent with cells of hematopoietic origin. The latter subset was found to be enriched with prosurfactant protein-C and SCGB1A1 expressing putative stem cells and with aquaporin-5 producing cells, characteristic of terminally differentiated alveolar epithelial type-1 pneumocytes. AICs undergo remodeling to form a cellular lining at the air/gel interface, and TGFβ1 treatment modifies protein expression, implying direct-differentiation of this population. These data confirm the active participation of clonogenic hematopietic stem cells in a mammalian model of lung repair and validate mixed stem/somatic cell cultures, which embrace sustained cell viability, proliferation, and differentiation, for use in studies of compensatory pulmonary growth. PMID:22585451

  15. Complete genome of the cellyloytic thermophile Acidothermus cellulolyticus 11B provides insights into its ecophysiological and evloutionary adaptations

    SciTech Connect

    Barabote, Ravi D.; Xie, Gary; Leu, David H.; Normand, Philippe; Necsulea, Anamaria; Daubin, Vincent; Medigue, Claudine; Adney, William S.; Xu,Xin Clare; Lapidus, Alla; Detter, Chris; Pujic, Petar; Bruce, David; Lavire, Celine; Challacombe, Jean F.; Brettin, Thomas S.; Berry, Alison M.

    2009-01-01

    We present here the complete 2.4 Mb genome of the cellulolytic actinobacterial thermophile, Acidothermus cellulolyticus 11B. New secreted glycoside hydrolases and carbohydrate esterases were identified in the genome, revealing a diverse biomass-degrading enzyme repertoire far greater than previously characterized, and significantly elevating the industrial value of this organism. A sizable fraction of these hydrolytic enzymes break down plant cell walls and the remaining either degrade components in fungal cell walls or metabolize storage carbohydrates such as glycogen and trehalose, implicating the relative importance of these different carbon sources. A novel feature of the A. cellulolyticus secreted cellulolytic and xylanolytic enzymes is that they are fused to multiple tandemly arranged carbohydrate binding modules (CBM), from families 2 and 3. Interestingly, CBM3 was found to be always N-terminal to CBM2, suggesting a functional constraint driving this organization. While the catalytic domains of these modular enzymes are either diverse or unrelated, the CBMs were found to be highly conserved in sequence and may suggest selective substrate-binding interactions. For the most part, thermophilic patterns in the genome and proteome of A. cellulolyticus were weak, which may be reflective of the recent evolutionary history of A. cellulolyticus since its divergence from its closest phylogenetic neighbor Frankia, a mesophilic plant endosymbiont and soil dweller. However, ribosomal proteins and non-coding RNAs (rRNA and tRNAs) in A. cellulolyticus showed thermophilic traits suggesting the importance of adaptation of cellular translational machinery to environmental temperature. Elevated occurrence of IVYWREL amino acids in A. cellulolyticus orthologs compared to mesophiles, and inverse preferences for G and A at the first and third codon positions also point to its ongoing thermoadaptation. Additional interesting features in the genome of this cellulolytic, hot

  16. CO2 over the past 5 million years: Continuous simulation and new δ11B-based proxy data

    NASA Astrophysics Data System (ADS)

    Stap, Lennert B.; de Boer, Bas; Ziegler, Martin; Bintanja, Richard; Lourens, Lucas J.; van de Wal, Roderik S. W.

    2016-04-01

    During the past five million yrs, benthic δ18O records indicate a large range of climates, from warmer than today during the Pliocene Warm Period to considerably colder during glacials. Antarctic ice cores have revealed Pleistocene glacial-interglacial CO2 variability of 60-100 ppm, while sea level fluctuations of typically 125 m are documented by proxy data. However, in the pre-ice core period, CO2 and sea level proxy data are scarce and there is disagreement between different proxies and different records of the same proxy. This hampers comprehensive understanding of the long-term relations between CO2, sea level and climate. Here, we drive a coupled climate-ice sheet model over the past five million years, inversely forced by a stacked benthic δ18O record. We obtain continuous simulations of benthic δ18O, sea level and CO2 that are mutually consistent. Our model shows CO2 concentrations of 300 to 470 ppm during the Early Pliocene. Furthermore, we simulate strong CO2 variability during the Pliocene and Early Pleistocene. These features are broadly supported by existing and new δ11B-based proxy CO2 data, but less by alkenone-based records. The simulated concentrations and variations therein are larger than expected from global mean temperature changes. Our findings thus suggest a smaller Earth System Sensitivity than previously thought. This is explained by a more restricted role of land ice variability in the Pliocene. The largest uncertainty in our simulation arises from the mass balance formulation of East Antarctica, which governs the variability in sea level, but only modestly affects the modeled CO2 concentrations.

  17. Complete genome of the cellulolytic thermophile Acidothermus cellulolyticus 11B provides insights into its ecophysiological and evolutionary adaptations

    SciTech Connect

    Xie, Gary; Detter, John C; Bruce, David C; Challacombe, Jean F; Brettin, Thomas S; Necsulea, Anamaria; Daubin, Vincent; Medigue, Claudine; Adney, William S; Xu, Xin C; Lapidus, Alla; Pujic, Pierre; Berry, Alison M; Barabote, Ravi D; Leu, David; Normand, Phillipe

    2009-01-01

    We present here the complete 2.4 MB genome of the actinobacterial thermophile, Acidothermus cellulolyticus 11B, that surprisingly reveals thermophilic amino acid usage in only the cytosolic subproteome rather than its whole proteome. Thermophilic amino acid usage in the partial proteome implies a recent, ongoing evolution of the A. cellulolyticus genome since its divergence about 200-250 million years ago from its closest phylogenetic neighbor Frankia, a mesophilic plant symbiont. Differential amino acid usage in the predicted subproteomes of A. cellulolyticus likely reflects a stepwise evolutionary process of modern thermophiles in general. An unusual occurrence of higher G+C in the non-coding DNA than in the transcribed genome reinforces a late evolution from a higher G+C common ancestor. Comparative analyses of the A. cellulolyticus genome with those of Frankia and other closely-related actinobacteria revealed that A. cellulolyticus genes exhibit reciprocal purine preferences at the first and third codon positions, perhaps reflecting a subtle preference for the dinucleotide AG in its mRNAs, a possible adaptation to a thermophilic environment. Other interesting features in the genome of this cellulolytic, hot-springs dwelling prokaryote reveal streamlining for adaptation to its specialized ecological niche. These include a low occurrence of pseudo genes or mobile genetic elements, a flagellar gene complement previously unknown in this organism, and presence of laterally-acquired genomic islands of likely ecophysiological value. New glycoside hydrolases relevant for lignocellulosic biomass deconstruction were identified in the genome, indicating a diverse biomass-degrading enzyme repertoire several-fold greater than previously characterized, and significantly elevating the industrial value of this organism.

  18. Cloning, Expression, and Characterization of a Thermophilic Endoglucanase, AcCel12B from Acidothermus cellulolyticus 11B

    PubMed Central

    Wang, Junling; Gao, Gui; Li, Yuwei; Yang, Liangzhen; Liang, Yanli; Jin, Hanyong; Han, Weiwei; Feng, Yan; Zhang, Zuoming

    2015-01-01

    The gene ABK52392 from the thermophilic bacterium Acidothermus cellulolyticus 11B was predicted to be endoglucanase and classified into glycoside hydrolase family 12. ABK52392 encodes a protein containing a catalytic domain and a carbohydrate binding module. ABK52392 was cloned and functionally expressed in Escherichia coli. After purification by Ni-NTA agarose affinity chromatography and Q-Sepharose® Fast Flow chromatography, the properties of the recombinant protein (AcCel12B) were characterized. AcCel12B exhibited optimal activity at pH 4.5 and 75 °C. The half-lives of AcCel12B at 60 and 70 °C were about 90 and 2 h, respectively, under acidic conditions. The specific hydrolytic activities of AcCel12B at 70 °C and pH 4.5 for sodium carboxymethylcellulose (CMC) and regenerated amorphous cellulose (RAC) were 118.3 and 104.0 U·mg−1, respectively. The Km and Vmax of AcCel12B for CMC were 25.47 mg·mL−1 and 131.75 U·mg−1, respectively. The time course of hydrolysis for RAC was investigated by measuring reducing ends in the soluble and insoluble phases. The total hydrolysis rate rapidly decreased after the early stage of incubation and the generation of insoluble reducing ends decreased earlier than that of soluble reducing ends. High thermostability of the cellulase indicates its potential commercial significance and it could be exploited for industrial application in the future. PMID:26506341

  19. Food Waste Composting Study from Makanan Ringan Mas

    NASA Astrophysics Data System (ADS)

    Kadir, A. A.; Ismail, S. N. M.; Jamaludin, S. N.

    2016-07-01

    The poor management of municipal solid waste in Malaysia has worsened over the years especially on food waste. Food waste represents almost 60% of the total municipal solid waste disposed in the landfill. Composting is one of low cost alternative method to dispose the food waste. This study is conducted to compost the food waste generation in Makanan Ringan Mas, which is a medium scale industry in Parit Kuari Darat due to the lack knowledge and exposure of food waste recycling practice. The aim of this study is to identify the physical and chemical parameters of composting food waste from Makanan Ringan Mas. The physical parameters were tested for temperature and pH value and the chemical parameter are Nitrogen, Phosphorus and Potassium. In this study, backyard composting was conducted with 6 reactors. Tapioca peel was used as fermentation liquid and soil and coconut grated were used as the fermentation bed. Backyard composting was conducted with six reactors. The overall results from the study showed that the temperature of the reactors were within the range which are from 30° to 50°C. The result of this study revealed that all the reactors which contain processed food waste tend to produce pH value within the range of 5 to 6 which can be categorized as slightly acidic. Meanwhile, the reactors which contained raw food waste tend to produce pH value within the range of 7 to 8 which can be categorized as neutral. The highest NPK obtained is from Reactor B that process only raw food waste. The average value of Nitrogen is 48540 mg/L, Phosphorus is 410 mg/L and Potassium is 1550 mg/L. From the comparison with common chemical fertilizer, it shows that NPK value from the composting are much lower than NPK of the common chemical fertilizer. However, comparison with NPK of organic fertilizer shown only slightly difference value in NPK.

  20. Simultaneously cycled NMR spectroscopy.

    PubMed

    Parish, David M; Szyperski, Thomas

    2008-04-09

    Simultaneously cycled (SC) NMR was introduced and exemplified by implementing a set of 2-D [1H,1H] SC exclusive COSY (E.COSY) NMR experiments, that is, rf pulse flip-angle cycled (SFC), rf pulse phase cycled (SPC), and pulsed field gradient (PFG) strength cycled (SGC) E.COSY. Spatially selective 1H rf pulses were applied as composite pulses such that all steps of the respective cycles were affected simultaneously in different slices of the sample. This increased the data acquisition speed for an n-step cycle n-fold. A high intrinsic sensitivity was achieved by defining the cycles in a manner that the receiver phase remains constant for all steps of the cycle. Then, the signal resulting from applying the cycle corresponded to the sum of the signals from all steps of the cycle. Hence, the detected free induction decay did not have to be separated into the contributions arising from different slices, and read-out PFGs, which not only greatly reduce sensitivity but also negatively impact lineshapes in the direct dimension, were avoided. The current implementation of SFC E.COSY reached approximately 65% of the intrinsic sensitivity of the conventional phase cycled congener, making this experiment highly attractive whenever conventional data acquisition is sampling limited. Highly resolved SC E.COSY yielding accurate 3J-coupling values was recorded for the 416 Da plant alkaloid tomatidine within 80 min, that is, 12 times faster than with conventional phase cycled E.COSY. SC NMR is applicable for a large variety of NMR experiments and thus promises to be a valuable addition to the arsenal of approaches for tackling the NMR sampling problem to avoid sampling limited data acquisition.

  1. Accurate Ab Initio Calculation of the Isotopic Exchange Equilibrium 10B(OH)3 + 11B(OH)4- = 11B(OH)3 + 10B(OH)4- In Aqueous Solution

    NASA Astrophysics Data System (ADS)

    Tossell, J. A.

    2005-12-01

    For more than a decade the B isotopic compositions of marine carbonates have been used as paleo-pH proxies for seawater and to reconstruct paleo-[CO2] concentrations in the atmosphere. A necessary step is this process is the accurate determination of the equilibrium constant, K, for the reaction shown in the title above. This equilibrium constant has been recently calculated using ab initio quantum chemical methods applied to nanoclusters containing the solutes B(OH)3 and B(OH)4- coordinated by large numbers of explicit solvent molecules, a computationally difficult procedure. To obtain the most accurate possible value for K the calculated vibrational frequencies were scaled to best fit the limited experimental data available. The value of K obtained (@ 25°C) was 1.027 (significantly larger than the long used value of 1.0194). Even more recently a purely experimental value of K= 1.0265 ± 0.0015 has been obtained through an accurate spectrophotometric determination of the difference of pKa's of commercially available bulk samples of >99% enriched 10B(OH)3(s) and 11B(OH)3 (s). Since we now know the correct experimental value and have a calculation, admittedly a difficult and slightly parameterized one, which matches the experimental result (which was obtained after the calculation), it is worthwhile to analyze the steps in the theoretical calculation of K in more detail. We need to establish a general procedure which can yield accurate K values for other similar aqueous species even if we have no accurate experimental value for K and no vibrational spectral data. To this end we will examine the dependence of the calculated values of vibrational frequencies, isotopomer frequency differences and K values on a number of factors, including (a) the quantum mechanical level (basis set and treatment of electron correlation) used for the free solutes, (b) the incorporation of aqueous medium effects, (c) the effects of vibrational anharmonicity, (d) incorporation of the

  2. Solid-state NMR study of various mono- and divalent cation forms of the natural zeolite natrolite.

    PubMed

    Park, Min Bum; Vicente, Aurélie; Fernandez, Christian; Hong, Suk Bong

    2013-05-28

    Here we present the one-dimensional (29)Si and (27)Al MAS NMR and two-dimensional (27)Al MQMAS and DQF-STMAS NMR spectra of the monovalent (Na(+), K(+), Rb(+), Cs(+) and NH4(+)) and divalent (Ca(2+), Sr(2+) and Ba(2+)) cation forms of the natural zeolite natrolite (framework type NAT) with complete Si-Al ordering over the crystallographically distinct tetrahedral sites and with the same hydration state (hydrated, partially dehydrated or fully dehydrated). In the case of monovalent cation-exchanged natrolites, the differences in their crystal symmetry evidenced by (29)Si MAS NMR were found to be in good agreement with those determined by crystallographic analyses. However, (27)Al DQF-STMAS NMR spectroscopy shows the presence of two distinct Al sites in dehydrated K-NAT, Rb-NAT and NH4-NAT, suggesting that their actual crystal symmetry is lower than the reported one (i.e., orthorhombic Fdd2). The MAS NMR results also show that the space group of hydrated Ca-NAT is lower than that (monoclinic F1d1) of hydrated scolecite, the natural calcium counterpart of natrolite, which is also the case with hydrated Sr-NAT and Ba-NAT. We believe that the unexpected diversity in the crystal symmetry of natrolite caused by exchange of various mono- and divalent ions, as well as by dehydration, may be inherently due to the high framework flexibility of this natural zeolite.

  3. Studying Dynamics by Magic-Angle Spinning Solid-State NMR Spectroscopy: Principles and Applications to Biomolecules

    PubMed Central

    Schanda, Paul; Ernst, Matthias

    2016-01-01

    Magic-angle spinning solid-state NMR spectroscopy is an important technique to study molecular structure, dynamics and interactions, and is rapidly gaining importance in biomolecular sciences. Here we provide an overview of experimental approaches to study molecular dynamics by MAS solid-state NMR, with an emphasis on the underlying theoretical concepts and differences of MAS solid-state NMR compared to solution-state NMR. The theoretical foundations of nuclear spin relaxation are revisited, focusing on the particularities of spin relaxation in solid samples under magic-angle spinning. We discuss the range of validity of Redfield theory, as well as the inherent multi-exponential behavior of relaxation in solids. Experimental challenges for measuring relaxation parameters in MAS solid-state NMR and a few recently proposed relaxation approaches are discussed, which provide information about time scales and amplitudes of motions ranging from picoseconds to milliseconds. We also discuss the theoretical basis and experimental measurements of anisotropic interactions (chemical-shift anisotropies, dipolar and quadrupolar couplings), which give direct information about the amplitude of motions. The potential of combining relaxation data with such measurements of dynamically-averaged anisotropic interactions is discussed. Although the focus of this review is on the theoretical foundations of dynamics studies rather than their application, we close by discussing a small number of recent dynamics studies, where the dynamic properties of proteins in crystals are compared to those in solution. PMID:27110043

  4. NMR in rotating magnetic fields: Magic angle field spinning

    SciTech Connect

    Sakellariou, D.; Meriles, C.; Martin, R.; Pines, A.

    2004-09-10

    Magic angle sample spinning has been one of the cornerstones in high-resolution solid state NMR. Spinning frequencies nowadays have increased by at least one order of magnitude over the ones used in the first experiments and the technique has gained tremendous popularity. It is currently a routine procedure in solid-state NMR, high-resolution liquid-state NMR and solid-state MRI. The technique enhances the spectral resolution by averaging away rank 2 anisotropic spin interactions thereby producing isotropic-like spectra with resolved chemical shifts and scalar couplings. Andrew proposed that it should be possible to induce similar effects in a static sample if the direction of the magnetic field is varied, e.g., magic-angle rotation of the B0 field (B0-MAS) and this has been recently demonstrated using electromagnetic field rotation. Here we discuss on the possibilities to perform field rotation using alternative hardware, together with spectroscopic methods to recover isotropic resolution even in cases where the field is not rotating at the magic angle. Extension to higher magnetic fields would be beneficial in situations where the physical manipulation of the sample is inconvenient or impossible. Such situations occur often in materials or biomedical samples where ''ex-situ'' NMR spectroscopy and imaging analysis is needed.

  5. Quantitative analysis of Earth's field NMR spectra of strongly-coupled heteronuclear systems.

    PubMed

    Halse, Meghan E; Callaghan, Paul T; Feland, Brett C; Wasylishen, Roderick E

    2009-09-01

    In the Earth's magnetic field, it is possible to observe spin systems consisting of unlike spins that exhibit strongly coupled second-order NMR spectra. Such spectra result when the J-coupling between two unlike spins is of the same order of magnitude as the difference in their Larmor precession frequencies. Although the analysis of second-order spectra involving only spin-(1/2) nuclei has been discussed since the early days of NMR spectroscopy, NMR spectra involving spin-(1/2) nuclei and quadrupolar (I>(1/2)) nuclei have rarely been treated. Two examples are presented here, the tetrahydroborate anion, BH4-, and the ammonium cation, NH4+. For the tetrahydroborate anion, (1)J((11)B,(1)H)=80.9Hz, and in an Earth's field of 53.3microT, nu((1)H)=2269Hz and nu((11)B)=728Hz. The (1)H NMR spectra exhibit features that both first- and second-order perturbation theory are unable to reproduce. On the other hand, second-order perturbation theory adequately describes (1)H NMR spectra of the ammonium anion, (14)NH4+, where (1)J((14)N,(1)H)=52.75Hz when nu((1)H)=2269Hz and nu((14)N)=164Hz. Contrary to an early report, we find that the (1)H NMR spectra are independent of the sign of (1)J((14)N,(1)H). Exact analysis of two-spin systems consisting of quadrupolar nuclei and spin-(1/2) nuclei are also discussed.