Crystal structures of 1,4-diaza bicyclo[2.2.2.]octane and N,N-dimethyl formamide adducts of copper acetate

The crystal structures of copper acetate adducts with 1,4-diaza bicyclo [2.2.2.]octane and N,N-dimethyl formamide are shown to be dimeric with Cu---Cu distances of 2.633 Å and 2.616 Å respectively.

Ion extraction from a plasma through a conical orifice

A method of ion extraction from plasmas is reported in which the interference of field lines due to the extraction system in the plasma region is avoided by proper shaping of the extractor electrode and is supported by field plots.

Infrared spectroscopic study of the rotation of the NH 4+ ion in ammonium halides

Infrared correlation functions, have been obtained from the analysis of band shapes of the 1400 cm−1 bending mode of NH4Cl, NH4Br and NH4I in both the Pm3m and Fm3m phases. The NH 4 + ion seems to undergo relatively free rotation in the high temperature Fm3m phases of these halides.

The nature of non-equilibrium solidification of undercooled Agsingle bondCu alloys in contact with primary copper dendrites

Liquids of silver-copper alloys with near eutectic compositions embedded in a copper matrix were undercooled. The structural and microstructural investigations of these alloys solidified from undercooled temperature indicated the absence of both the eutectic reaction and diffusionless transformation below the equal free energy curve (T0). Instead the liquid maintained local equilibrium with the copper dendrites continuously until it intersected the extended solidus of the silver rich solid solution.

Characterization of Ion-Exchange Fibers for Controlled Drug Delivery

Increasing attention has been focused on methods that deliver pharmacologically active compounds (e.g. drugs, peptides and proteins) in a controlled fashion, so that constant, sustained, site-specific or pulsatile action can be attained. Ion-exchange resins have been widely studied in medical and pharmaceutical applications, including controlled drug delivery, leading to commercialisation of some resin based formulations. Ion-exchangers provide an efficient means to adjust and control drug delivery, as the electrostatic interactions enable precise control of the ion-exchange process and, thus, a more uniform and accurate control of drug release compared to systems that are based only on physical interactions. Unlike the resins, only few studies have been reported on ion-exchange fibers in drug delivery. However, the ion-exchange fibers have many advantageous properties compared to the conventional ion-exchange resins, such as more efficient compound loading into and release from the ion-exchanger, easier incorporation of drug-sized compounds, enhanced control of the ion-exchange process, better mechanical, chemical and thermal stability, and good formulation properties, which make the fibers attractive materials for controlled drug delivery systems. In this study, the factors affecting the nature and strength of the binding/loading of drug-sized model compounds into the ion-exchange fibers was evaluated comprehensively and, moreover, the controllability of subsequent drug release/delivery from the fibers was assessed by modifying the conditions of external solutions. Also the feasibility of ion-exchange fibers for simultaneous delivery of two drugs in combination was studied by dual loading. Donnan theory and theoretical modelling were applied to gain mechanistic understanding on these factors. The experimental results imply that incorporation of model compounds into the ion-exchange fibers was attained mainly as a result of ionic bonding, with additional contribution of non-specific interactions. Increasing the ion-exchange capacity of the fiber or decreasing the valence of loaded compounds increased the molar loading, while more efficient release of the compounds was observed consistently at conditions where the valence or concentration of the extracting counter-ion was increased. Donnan theory was capable of fully interpreting the ion-exchange equilibria and the theoretical modelling supported precisely the experimental observations. The physico-chemical characteristics (lipophilicity, hydrogen bonding ability) of the model compounds and the framework of the fibrous ion-exchanger influenced the affinity of the drugs towards the fibers and may, thus, affect both drug loading and release. It was concluded that precisely controlled drug delivery may be tailored for each compound, in particularly, by choosing a suitable ion-exchange fiber and optimizing the delivery system to take into account the external conditions, also when delivering two drugs simultaneously.

Copper-doped mesoporous silica nanospheres, a promising immunomodulatory agent for inducing osteogenesis

The application of mesoporous silica nanospheres (MSNs) loaded with drugs/growth factors to induce osteogenic differentiation of stem cells has been trialed by a number of researchers recently. However, limitations such as high cost, complex fabrication and unintended side effects from supraphysiological concentrations of the drugs/growth factors represent major obstacles to any potential clinical application in the near term. In this study we reported an in situ one-pot synthesis strategy of MSNs doped with hypoxia-inducing copper ions and systematically evaluated the nanospheres by in vitro biological assessments. The Cu-containing mesoporous silica nanospheres (Cu-MSNs) had uniform spherical morphology (∼100 nm), ordered mesoporous channels (∼2 nm) and homogeneous Cu distribution. Cu-MSNs demonstrated sustained release of both silicon (Si) and Cu ions and controlled degradability. The Cu-MSNs were phagocytized by immune cells and appeared to modulate a favorable immune environment by initiating proper pro-inflammatory cytokines, inducing osteogenic/angiogenic factors and suppressing osteoclastogenic factors by the immune cells. The immune microenvironment induced by the Cu-MSNs led to robust osteogenic differentiation of bone mesenchymal stem cells (BMSCs) via the activation of Oncostation M (OSM) pathway. These results suggest that the novel Cu-MSNs could be used as an immunomodulatory agent with osteostimulatory capacity for bone regeneration/therapy application. Statement of significance In order to stimulate both osteogenesis and angiogenesis of stem cells for further bone regeneration, a new kind of hypoxia-inducing copper doped mesoporous silica nanospheres (Cu-MSNs) were prepared via one-pot synthesis. Biological assessments under immune environment which better reflect the in vivo response revealed that the nanospheres possessed osteostimulatory capacity and had potential as immunomodulatory agent for bone regeneration/therapy application. The strategy of introducing controllable amount of therapeutic ions instead of loading expensive drugs/growth factors in mesoporous silica nanosphere provides new options for bioactive nanomaterial functionalization.

Composite field approximations for ion traps with apertures on electrodes

This paper presents two approximate analytical expressions for nonlinear electric fields in the principal direction in axially symmetric (3D) and two dimensional (2D) ion trap mass analysers with apertures (holes in case of 3D traps and slits in case of 2D traps) on the electrodes. Considered together (3D and 2D), we present composite approximations for the principal unidirectional nonlinear electric fields in these ion traps. The composite electric field E has the form E = E-noaperture + E-aperture. where E-noaperture is the field within an imagined trap which is identical to the practical trap except that the apertures are missing and E-aperture is the field contribution due to apertures on the two trap electrodes. The field along the principal axis, of the trap can in this way be well approximated for any aperture that is not too large. To derive E-aperture. classical results of electrostatics have been extended to electrodes with finite thickness and different aperture shapes.E-noaperture is a modified truncated multipole expansion for the imagined trap with no aperture. The first several terms in the multipole expansion are in principle exact(though numerically determined using the BEM), while the last term is chosen to match the field at the electrode. This expansion, once Computed, works with any aperture in the practical trap. The composite field approximation for axially symmetric (3D) traps is checked for three geometries: the Paul trap, the cylindrical ion trap (CIT) and an arbitrary other trap. The approximation for 2D traps is verified using two geometries: the linear ion trap (LIT) and the rectilinear ion trap (RIT). In each case, for two aperture sizes (10% and 50% of the trap dimension), highly satisfactory fits are obtained. These composite approximations may be used in more detailed nonlinear ion dynamics Studies than have been hitherto attempted. (C) 2009 Elsevier B.V. All rights reserved.

Dynamics of the ammonium ion in the ferroelectric transition in sodium ammonium selenate, NaNH4SeO4·2H2O-an E.S.R. study

E.S.R. investigations of γ-irradiated ferroelectric Sodium ammonium selenate, NaNH4SeO4•2H2O and its deuteriated analogue in powder and single crystal forms have led to a deeper understanding of the nature of the ferroelectric transition of 180 K. A number of paramagnetic species formed due to γ-irradiation have been identified on the basis of their g-factors and hyperfine features from 77Se. The radical SeO4 has been used as a microprobe in studying the phase transition.

Resistivity Maxima in Lithium Fast-Ion Conductors at High Pressure

The resistivity of two types of lithium fast-ion conductors, Li16-2xZnx(GeO4)4 (x=1,2) and Li3+xGexV1-xO4 (x=0.25,0.6,0.72), showed pronounced maxima as a function of pressure. For the first type, ln(ρ / ρ0) peaked at values of 0.12 (x=1) and 0.35 (x=2) near 20 kbar and decreased thereafter up to 80 kbar. Thermal activation energies and prefactors also showed corresponding maxima. For the second type, ln(ρ / ρ0) increased to 3-4 between 20 and 32 kbar. Near 80 kbar, ρ decreased (for x=0.25) by a factor of 250. The results are interpreted in terms of negative activation volumes.

Field evaluation of a plant activator, captan, chlorothalonil, copper hydroxide, iprodione, mancozeb and strobilurins for the control of citrus brown spot of mandarin

Brown spot (caused by Alternaria alternata) is a major disease of citrus in subtropical areas of Australia. A number of chemicals, the strobilurins azoxystrobin, trifloxystrobin, pyraclostrobin and methoxycrylate, a plant activator (acibenzolar), copper hydroxide, mancozeb, captan, iprodione and chlorothalonil/pyrimthanil were tested in the field for its control. Over three seasons, trees in a commercial orchard received 16, 14 and 7 fungicide sprays, respectively, commencing at flowering in the first season, and petal fall in the later seasons. In all experiments, the strobilurins used alone, or incorporated with copper and mancozeb, were as effective as, or better than the industry standard of copper and mancozeb alone. The only exception was trifloxystrobin, which when used alone was less effective than the industry standard. Acibenzolar used alone was ineffective. Applying a mixture of azoxystrobin and acibenzolar was found to reduce the incidence of brown spot compared with applying azoxystrobin alone but, in either case, disease levels were not found to be significantly different to the industry standard. Captan, iprodione and chlorothalonil/pyrimthanil were as effective as the industry standard. The incidence and severity of rind damage were significantly lowest in the azoxystrobin, methoxycrylate, iprodione and chlorothalonil/pyrimthanil treatments. Medium and high rates of trifloxystrobin (0.07 g/L, 0 .15 g/L) and pyraclostrobin (0.8 g/L, 1.2 g/L) applied alone were the only treatments found to be IPM-incompatible as shown by the elevated level of scale infection on fruit.

Oxidative extraction and ion-exchange of lithium in Li2MoO3: synthesis of Li2âxMoO3 and H2MoO3

It is shown that lithium can be oxidatively extracted from Li2MoO3 at room temperature using Br2 in CHCl3. The delithiated oxides, Li2â��xMoO3 (0 < x â�¤ 1.5) retain the parent ordered rocksalt structure. Complete removal of lithium from Li2MoO3 using Br2 in CH3CN results in a poorly crystalline MoO3 that transforms to the stable structure at 280�°C. Li2MoO3 undergoes topotactic ion-exchange in aqueous H2SO4 to yield a new protonated oxide, H2MoO3.

Magnesium/Copper Nanocomposite through Digestive Ripening

Composing nanocomposites: Co-digestive ripening of as-prepared Mg and Cu colloids prepared by the solvated metal atom dispersion method results in a highly monodisperse colloid of Mg/Cu nanocomposite with an average particle size of 3.0 +/- 0.5 nm. Annealing of these samples at 300 degrees C gives the Cu/MgO nanocomposite.

HNbWO6 and HTaWO6: Novel oxides related to ReO3 formed by ion exchange of rutile-type LiNbWO6 and LiTaWO6

Both LiNbWO6 and LiTaWO6 undergo ion exchange in hot aqueous H2SO4 yielding the hydrates HMWO6 · H2O (M = Nb or Ta). The reaction is accompanied by a structural transformation from the rutile to the ReO3 structure. The cell constants are a = 3.783(3)Å for HNbWO6 · H2O and a = 3.785(5)Å for HTaWO6 · H2O. The ReO3 structure is retained by the dehydration products HMWO6 and MWO5.5 as well. HMWO6 phases yield H1+xMWO6 hydrogen bronzes on exposure to hydrogen in the presence of platinum catalyst.