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Abstract Oxidative polymerization for the manufacture of conducting polymers such as poly(3,4-ethylenedioxy-thiophene) has traditionally employed iron(III) salts. Demonstrated in this study is vapour phase polymerization of 3,4-ethylenedio- xythiophene using a metal-free oxidant, ammonium persulfate, leading to films with an estimated conductivity of 75 S/cm. Additionally, a route for embedding active transition metal complexes into these poly(3,4-ethylenedioxythiophene)/-poly(styrene-4-sulfonate) (PEDOT/PSS) films via vapour assisted complexation is outlined. Here, the vapour pressure of solid ligands around their melting temperatures was exploited to ensure complexation to metal ions added into the oxidant mixture prior to polymerization of PEDOT. Four composite systems are discussed, viz. PEDOT/PSS embedded with tris(8-hydroxyquinolinato)cobalt(III), tris(2,2-bipyridine)cobalt(II), tris(1,10- phenanthroline)cobalt(II) and tris(8-hyd-roxyquinolinato)aluminium(III). Using these composites, electrochemical reduction of nitrite to ammonia with a faradaic efficiency of 61% was reported.
The rates and activation parameters of water exchange at pH 3.0 have been determined using variable temperature 17O NMR spectroscopy for four CoII complexes and one MnII complex: [Co(bpy)(H2O)4]2+, [Co(bpy)2 (H2O)2]2+, [Co(phen)-(H2O)4]2+, [Co(phen)2 (H2O)2]2+, and [Mn(bpy)(H2O)4]2+ (bpy = 2,2′-bipyridyl and phen = 1,10-phenanthroline). Substitution of aquo ligands with 1,10-phenanthroline or 2,2′-bipyridyl leads to an increase in the rate of exchange in the manganese complexes, from k298 (1.8 ± 0.1) × 107 s-1 for [Mn(H2O)6]2+ to (7.2 ± 0.3) × 107 s-1 for [Mn(phen)2 (H2O)2]2+, whereas the trends are more complex for the cobalt complexes. We have used the new data in conjunction with literature data for similar complexes to analyse the effect of M–OH2 distance and degree of substitution.
Cellular uptake of inorganic divalent mercury (Hg(II)) is a key step in microbial formation of neurotoxic methylmercury (MeHg), but the mechanisms remain largely unidentified. We show that the iron reducing bacterium Geobacter sulfurreducens produces and exports appreciable amounts of low molecular mass thiol (LMM-RSH) compounds reaching concentrations of about 100 nM in the assay medium. These compounds largely control the chemical speciation and bioavailability of Hg(II) by the formation of Hg(LMM-RS)<INF><INF><INF>2</INF></INF> </INF>complexes (primarily with cysteine) in assays without added thiols. By characterizing these effects, we show that the thermodynamic stability of Hg(II)-complexes is a principal controlling factor for Hg(II) methylation by this bacterium such that less stable complexes with mixed ligation involving LMM-RSH, OH-, and Cl- are methylated at higher rates than the more stable Hg(LMM-RS)<INF>2</INF> complexes. The Hg(II) methylation rate across different Hg(LMM-RS)<INF>2</INF> compounds is also influenced by the chemical structure of the complexes. In contrast to the current perception of microbial uptake of Hg, our results adhere to generalized theories for metal biouptake based on metal complexation with cell surface ligands and refine the mechanistic understanding of Hg(II) availability for microbial methylation.
In the search for trace amounts of explosives in various environmental samples, the
analytical procedure is in need of improvements. If it is for national security or for
environmental purposes the detection of trace amounts of for example 2,4,6-
trinitrotoluene (TNT) is a costly and time consuming procedure. The use of Raman
spectrometry for trace amounts detection is one of the research areas that are in the
advancement and mainly because of the discovery of Surface-Enhanced Raman
spectroscopy (SERS). Raman spectrometry detects the inelastically scattered light
from molecules giving a fingerprint spectrum that can be interpreted and species can
be detected. The inelastically scattering of light only occurs in a small amount of the
molecules making the signal low and sensitive for interferences. SERS enhances the
signal from the molecules making it possible to detect very low concentrations. The
surfaces used in SERS need to be selective for the wanted species to be useful for the
analysis of environmental samples that often contains a wide variety of compounds.
This project's aim was to investigate the possibility of modifying gold- and silvercoated
SERS surfaces (provided by DTU Nanotech) to get a selective detection of
trace amounts of TNT in water and air samples.
The results from the modification indicated some problems with the surfaces. The
modification molecules were cysteine or cysteamine. The hypothesis was that both of
them should bind to the surface by sulphur bond. But for cysteine this was not the
case. The results indicated a binding of the carboxyl group making the use of the
modification for the selective detection of TNT impossible. The modification by
cysteamine was more successful but the detection of TNT in water samples was hard
to get clear results from. The detection of TNT in air samples was carried out by a
method never tested before using a so-called Linkam cell in conjunction with a TNT
treated GC-column which together create a controlled environment. The results from
this experiment were very positive where a clear SERS-signal from TNT could be
Reversible interaction with carbon monoxide results in the onset of dynamic atropisomerism at 298 K in an otherwise static NHC-based rhodium pincer complex, [Rh(C boolean AND N boolean AND C-(CH2)(12))(CO)][BArF4] (1, ArF = 3,5-C6H3(CF3)(2)). The mechanism of this process has been comprehensively interrogated by a combination of variable-temperature NMR spectroscopy, IR spectroscopy, and computational modeling. In addition, a structural analogue of a high-energy symmetrical intermediate species-invoked in the process but not directly observed spectroscopically-has been prepared and characterized in solution and the solid-state.
This review covers recent advances in the understanding of the in vitro and in vivo effects of decavanadate, (V10O28)(6-), particularly in mitochondria. In vivo toxicological studies involving vanadium rarely account for the fact that under physiological conditions some vanadium may be present in the form of the decavanadate ion, which may behave differently from ortho- and metavanadates. It has for example been demonstrated that vanadium levels in heart or liver mitochondria are increased upon decavanadate exposure. Additionally, in vitro studies have shown that mitochondrial depolarization (IC50, 40 nM) and oxygen consumption (IC50, 99 nM) are strongly affected by decavanadate, which causes reduction of cytochrome b (complex III). We review these recent findings which together suggest that the observed cellular targets, metabolic pathway and toxicological effects differ according to the species of vanadium present. Finally, the toxicological effects of decavanadate depend on several factors such as the mode of administration, exposure time and type of tissue. (C) 2014 Elsevier Inc. All rights reserved.
The putative applications of poly-, oligo-and mono-oxometalates in biochemistry, biology, pharmacology and medicine are rapidly attracting interest. In particular, these compounds may act as potent ion pump inhibitors and have the potential to play a role in the treatment of e. g. ulcers, cancer and ischemic heart disease. However, the mechanism of action is not completely understood in most cases, and even remains largely unknown in other cases. In the present review we discuss the most recent insights into the interaction between mono-and polyoxometalate ions with ion pumps, with particular focus on the interaction of decavanadate with Ca2+-ATPase. We also compare the proposed mode of action with those of established ion pump inhibitors which are currently in therapeutic use. Of the 18 classes of compounds which are known to act as ion pump inhibitors, the complete mechanism of inhibition is only known for a handful. It has, however, been established that most ion pump inhibitors bind mainly to the E2 ion pump conformation within the membrane domain from the extracellular side and block the cation release. Polyoxometalates such as decavanadate, in contrast, interact with Ca2+-ATPase near the nucleotide binding site domain or at a pocket involving several cytoplasmic domains, and therefore need to cross through the membrane bilayer. In contrast to monomeric vanadate, which only binds to the E2 conformation, decavanadate binds to all protein conformations, i.e. E1, E1P, E2 and E2P. Moreover, the specific interaction of decavanadate with sarcoplasmic reticulum Ca2+-ATPase has been shown to be non-competitive with respect to ATP and induces protein cysteine oxidation with concomitant vanadium reduction which might explain the high inhibitory capacity of V-10 (IC50 = 15 mu M) which is quite similar to the majority of the established therapeutic drugs.
The decaniobate ion, (Nb-10 = [Nb10O28](6-)) being isoelectronic and isostructural with the decavanadate ion (V-10 = [V10O28](6-)), but chemically and electrochemically more inert, has been useful in advancing the understanding of V-10 toxicology and pharmacological activities. In the present study, the solution chemistry of Nb-10 and V-10 between pH 4 and 12 is studied by Raman spectroscopy. The Raman spectra of V-10 show that this vanadate species dominates up to pH 6.45 whereas it remains detectable until pH 8.59, which is an important range for biochemistry. Similarly, Nb-10 is present between pH 5.49 and 9.90 and this species remains detectable in solution up to pH 10.80. V-10 dissociates at most pH values into smaller tetrahedral vanadate oligomers such as V-1 and V-2, whereas Nb-10 dissociates into Nb-6 under mildly (10 > pH > 7.6) or highly alkaline conditions. Solutions of V-10 and Nb-10 are both kinetically stable under basic pH conditions for at least two weeks and at moderate temperature. The Raman method provides a means of establishing speciation in the difficult niobate system and these findings have important consequences for toxicology activities and pharmacological applications of vanadate and niobate polyoxometalates.
Partial oxidation of ethanol to acetaldehyde was carried out over gold catalysts supported on various oxides and zeolites by deposition precipitation. The special focus of this work was on the influence of H-Y zeolite surface charge on Au cluster size and loading linking it to activity and selectivity in ethanol oxidation and comparing with other studied catalysts. The catalysts were characterized by nitrogen physisorption, transmission electron microscopy (TEM), scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDXA), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and zeta potential measurements. pH of the solution governed the Au NPs size within the range of 5.8–13.2 nm with less negatively charged surfaces leading to formation of smaller clusters. Au loading on H-Y zeolite with silica to alumina ratio of 80 was increased by raising the pH. In fact, H-Y-12 and H-Beta-25 were selective towards diethyl ether while acetaldehyde was the prevalent product on less acidic H-Y-80. The results demonstrated strong dependency of the catalytic activity on the Au cluster size. Namely turn over frequency (TOF) decreased with an increase in metal size from 6.3 to 9.3 nm on H-Y-80. Selectivity towards acetaldehyde and ethyl acetate did not change significantly on H-Y-80 within 6.3–9.3 nm Au particle size range. On Al2O3 support, however, selectivity towards acetaldehyde increased considerably upon diminishing Au average particle size from 3.7 to 2.1 nm.
The determination of complexes formed in weakly acidic aqueous solutions containing pentavalent vanadium as well as hexavalent molybdenum has proved diffi cui t due to slow equilibria and 1 imi ted sol ubi 1 i ty of especially the vanadium species. The formation of several different polynuclear complexes with a very varied molybdenum/vanadium ratio also complicates the interpretation of Potentiometrie data. In order to clarify the picture of complexes formed and provide starting points for equilibrium calculations single-crystal X-ray studies were made on crystals obtained from âqueous solutions. In addition, these studies can provide information on bonding conditions and possibly formation mechanisms for molybdovanadate polyanions. Crystals were synthesized by slow evaporation of aqueous solutions. Solutions with varied molybdenum/vanadium ratios and also varied pH values were prepared and used in the synthesis experiments. The X-ray measurements were performed with Philips PAILRED, Syntex P21 and Syntex R3 automatic diffractometers. All data sets were corrected for absorption. Five of the structures were solved with heavy-atom methods and one by direct methods. The structures were refined by computer-performed least-squares methods. The following crystals were obtained and structurally determined: NaV03•1.89H2O, which contains chains of VO5 trigonal bipyramids. Na4V2O7 (H2O)18 , containing discrete V2O74- anions which are completely surrounded by sodium-coordinated water molecules. Discrete molybdovanadate polyanions were found in the structures of the compounds Na6Mo6\/2O26 (H2O)16 , K7Mo8V5O40 • 8H2O, K8Mo4,V8O36 - 12H20 and K6 (V2 , Mo10) VO40 • 13H20. The last substance belongs to a class of compounds named 'heteropoly blues', which contain metal atoms in mixed-valence states, and has one unpaired electron on the polyanion. This compound was also investigated with electron spin resonance spectroscopy. The bonding configurations of oxygen atoms coordinated to molybdenum or vanadium are described and discussed. As the Mo4V8O368-, Mo8V5O407- (which is an isomer of the Keggin anion but has a quite different structure) and Mo6V2O266- anions all contain remnants of mononuclear molybdate and vanadate anions, it seems likely that these polyanions are formed mainly through the condensation of mononuclear species.An electrostatic model for the simulation of bond distances in polyions, starting with perfectly regular idealized models, is presented.
Effects of mineral particle morphology and roughness on potential determining ion (p.d.i.; H+, OH−) loadings achieved at synthetic lepidocrocite (γ-FeOOH) surfaces were predominantly investigated by potentiometry and thermodynamic modeling. Nanosized rod- (RL) and lath-shaped (LL) particles exhibiting different proportions of the same predominant crystallographic faces acquired largely comparable pH, ionic strength and counterion (NaCl, NaClO4) dependencies on p.d.i. loadings. These results supported previous claims that faces ideally containing proton silent sites only, are likely populated by additional proton active sites. This concept was supported further by results of roughened LL-like particles (LLR) also showing highly congruent pH-, ionic strength- and composition-dependent p.d.i. loadings with those of LL and RL. These loadings thereby correspond to maximal levels allowed by net attractive and repulsive forces at each solution composition, irrespective of particle morphology. Contrasting equilibration times required to achieve these loadings revealed considerably slower exchange of p.d.i. and electrolyte ions near the point of zero charge in the rough LLR than in the more idealized LL and RL particles.
Thermodynamic modeling was used to test various concepts accounting for these results. The model made use of a novel framework capable of isolating electrostatic contributions from different faces, and of accounting for ion-specific double-layer properties within a single crystallographic face. These efforts made use of capacitance values for each electrolyte ions within the framework of a recently developed Variable Capacitance Model. Attempts at modeling all three particle types were used to suggest that the (0 1 0) face contains ∼0.9 site nm−2 of proton active sites, a value notably constrained by recently published Na+, Cl−, and ClO4− loadings derived by cryogenic X-ray photoelectron spectroscopy. The model presented in this work thus provides a means to predict p.d.i. loadings on multifaceted mineral particle surfaces, and can therefore be used to constrain further our understanding of mineral/water interface reactivity.
Two-dimensional (2D) correlation spectroscopy was used to resolve the positions and correlations among U4f primary peaks and satellite structures of UIV, UV and UVI components on a dry mica surface. These different species resulted from the reduction of UVI, initially sorbed/precipitated from solution, upon exposure to a high flux of monochromatic Al Kα X-rays during X-ray photoelectron spectroscopy. Synchronous and asynchronous 2D maps of these results are consistent with previous assignments to UIV, UV and UVI components of the solid. The synchronous spectra confirmed the negative correlation between UVI and UIV components and the asynchronous spectra confirmed the role of UV as a reactive intermediate in the reduction reaction of UVI to UIV. Simulations of 2D correlation maps using synthetic spectra of the primary peaks showed that the presence of highly overlapped peaks centered within 2 eV of each other cannot be distinguished without the presence of additional cross-peaks. The maps have therefore confirmed the existence of three dominant oxidation states, and identified positions of UIV, UV and UVI U4f primary peaks and satellite structures that are consistent with previous peak-fitting efforts. Satellite structures also showed out-of-phase correlations among the different oxidation states, further confirming their use as reliable indicators of oxidation state.
There is relatively extensive knowledge available concerning ash transformation reactions during energy conversion of woody biomass. Traditionally, these assortments have constituted the main resources for heating in Sweden. In recent decades the utilization of these energy carriers has increased, from a low technology residential small scale level to industrial scale (e.g. CHP plants). Along this evolution ash-chemical related phenomena for woody biomass has been observed and studied. So, presently the understanding for these are, if not complete, fairly good. Briefly, from a chemical point of view the ash from woody biomass could be characterized as a silicate dominated systems with varying content of basic oxides and with relatively high degree of volatilization of alkali sulfates and chlorides. Thus, the main ash transformation mechanisms in these systems have been outlined. Here, an attempt to give a general description of the ash transformation reactions of biomass fuels is presented, with the intention to provide guidance in the understanding of ash matter behavior in the utilization of any biomass fuel, primarily from knowledge of the concentrations of ash forming elements but also by considering the physical condition in the specific combustion appliance and the physical characteristic of the biomass fuel. Furthermore, since the demand for CO2-neutral energy resources has increased the last years and will continue to do so in the foreseeable future, other biomasses as for instance agricultural crops has become highly interesting. Globally, the availability of these shows large variation. In Sweden, for instance, which is a relatively spare populated country with large forests, these bio-masses will play a secondary role, although not insignificant. In other parts of the world, more densely populated and with a large agricultural sector, such bio-masses may constitute the main energy bio-mass resource in the future. However, the content of ash forming matter in agricultural bio-mass is rather different in comparison to woody biomass. Firstly, the content is much higher; from being about 0.3 – 0.5% (wt) in stem wood, it can amount to between 2 and 10 %(wt) in agricultural biomass. In addition, the composition of the ash forming matter is different. Shortly, the main difference is due to a much higher content of phosphorus (occasionally also silicon) which has major consequences on the ash-transformation reactions. In many crops, the concentration of phosphorus and silicon is equivalent, which (depending on the concentration levels of basic oxides) may result in a phosphate dominated ash. The properties of this ash are in several aspects different from the silicate dominated woody biomass ash and will consequently behave differently in various types of energy conversion systems. The knowledge about phosphate dominated ash systems has so far been scarce. We have been working with these systems, both with basic and applied research, for about a decade know. Some general experiences and conclusions as well as some specific examples of our research will be presented.
We studied the molecular packing and crystallization of a highly regio-regular semiconducting polymer poly(3-hexylthiophene) (P3HT) on both single layer graphene and silicon as a function of temperature, during cooling from the melt. The onset of crystallization, crystallites' size, orientation, and kinetics of formation were measured in situ by synchrotron grazing incidence X-ray diffraction (GIXD) during cooling and revealed a very different crystallization process on each surface. A favored crystalline orientation with out of plane pi-pi stacking formed at a temperature of 200 degrees C on graphene, whereas the first crystallites formed with an edge-on orientation at 185 degrees C on silicon. The crystallization of face-on lamellae revealed two surprising effects during cooling: (a) a constant low value of the pi-pi spacing below 60 degrees C; and (b) a reduction by half in the coherence length of face-on lamellae from 100 to 30 degrees C, which corresponded with the weakening of the 2nd or 3rd order of the in-plane (k00) diffraction peak. The final ratio of face-on to edge-on orientations was 40% on graphene, and 2% on silicon, revealing the very different crystallization mechanisms. These results provide a better understanding of how surfaces with different chemistries and intermolecular interactions with the polythiophene polymer chains lead to different crystallization processes and crystallites orientations for specific electronic applications.
Heteronuclear NMR experiments, in particular 51V, wereperformed with the aim to elucidate the nature of vanadates and peroxovanadates in hydrophilic ionic liquids (i.e., [bmim][BF4], [bmim][TfO] and [bdmim][BF4]). The data so far reported clearly indicate that ionic liquids have a strong influence on the solution chemistry of vanadate in water both for the formation of the aggregates (with and without H2O2) and for the rate of peroxide consumption catalyzed by vanadium. In BF4- containing ionic liquids, formation of vanadate-fluoride adducts is suggested. The obtained results are also discussed in the light of the reactivity data of peroxovanadates in ionic liquids.
Stem wood powders were fired in a mullite-lined pilot-scale oxygen-blown pressurized entrained-flow gasifier. During repeated campaigns involving increases in fuel load and process temperature, slag formations that eventuated in the blockage of the gasifier outlet were observed. These slags were retrieved for visual and chemical characterization. It was found that the slags had very high contents of Al and, in particular, high Al/Si ratios that suggest likely dissolution of the mullite-based refractory of the gasifier lining due to interactions with the fuel ash. Possible causes for the slag formation and behavior are proposed, and practical implications for the design of future stem wood entrained-flow gasifiers are also discussed
Clathrate hydrates with the cubic structure II (CS-II) form typically with large guest molecules, such as tetrahydrofuran, trimethylamine oxide, or propane. However, CS-II is also realized for argon hydrate despite the comparatively small van der Waals diameter of the guest (around 3.8 angstrom). Here, the structure of deuterated argon hydrate was studied at ambient pressure in the temperature range 20-95 K using neutron diffraction and comparing natural Ar with Ar-36, which scatters neutrons more than 13 times more efficiently. The procedure allowed to unambiguously establish the positional disorder within the large cages of CS-H, while simultaneously refining host and guest structures. These cages are singly occupied and off-centered argon atoms distribute on two tetrahedron-shaped split positions with a ratio 3:1. Molecular dynamics (MD) simulations revealed that the crystallographic positional disorder structure is due to mobile argon atoms even at 20 K. The MD potential energy distribution confirmed the diffraction model. It is noted that the unit cell volumes of argon hydrate in the investigated temperature range are virtually identical to N-2 hydrate, which has a similar composition at ambient pressure, indicating a very similar (slightly attractive) host-guest interaction.
Pilicides are a class of compounds that attenuate virulence in Gram negative bacteria by blocking the chaperone/usher pathway in Escherichia coli. It has also been shown that compounds derived from the peptidomimetic scaffold that the pilicides are based on can prevent both Aβ aggregation and curli formation. To facilitate optimizations towards the different targets, a new synthetic platform has been developed that enables fast and simple introduction of various substituents in position C-7 on the peptidomimetic scaffold. Importantly, this strategy also enables introduction of previously unattainable heteroatoms in this position. Pivotal to the synthetic strategy is the synthesis of a C-7 bromomethyl substituted derivative of the ring-fused dihydrothiazolo 2-pyridone pilicide scaffold. From this versatile and reactive intermediate various heteroatom-linked substituents could be introduced on the scaffold including amines, ethers, amides and sulfonamides. In addition, carbon-carbon bonds could be introduced to the sp(3)-hybridized bromomethyl substituted scaffold by Suzuki-Miyaura cross couplings. Evaluation of the 24 C-7 substituted compounds in whole-bacterial assays provided important structure-activity data and resulted in the identification of a number of new pilicides with activity as good or better than those developed previously.
Iron oxyhydroxides are of widespread occurrence in nature and play essential roles in both environmental as well as industrial processes. Due to their high reactivity, these minerals can act as sinks and/or transformation centers for a variety of inorganic and organic ions. These reactions are often mediated by various surface hydroxyl groups that are in turn singly-, doubly- or triply-coordinated with respect to underlying Fe atoms. In an effort to follow the reactivity of these different groups, attenuated total reflectance (ATR) - Fourier transform infrared (FTIR) spectroscopy was used to monitor adsorption reactions of on iron oxyhydroxide minerals.
This work was specifically focused on synthetic submicron-sized lepidocrocite and goethite particles reacted to aqueous solutions of sodium fluoride and sodium phosphate. Langmuir-Freundlich adsorption isotherms were calibrated on adsorption data at various pH values to provide independent clues to the maximum sorption density achieved by these ions. When compared to theoretical site densities, these values suggested that although singly-coordinated groups are by far the more reactive groups on all surfaces, doubly-coordinated groups could be substituted by fluoride ions. FTIR measurements of dry mineral samples equilibrated with fluoride and phosphate confirmed these findings and also showed that triply-coordinated groups cannot be exchanged.
Key words
: goethite, lepidocrocite, FTIR, surface, adsorption, isotherm, modeling
This paper presents the results of our XPS (X-ray photoelectron spectroscopy) and XANES (X-ray absorption near edge structure) Studies of tin oxide nanolayers obtained by magnetron spraying of the metal and its further oxidation in air at different temperatures. It was shown that at 240 degrees C (annealing temperature), tin monoxide was dominant in the surface layer of the samples. When the temperature was increased to 450 degrees C, the phase composition corresponded to tin dioxide. Increased sorption ability was found for the samples oxidized at 450 degrees C. The band structure model of SnOx nanolayers obtained by superposition of the XANES and XPS data revealed cross transitions with energy similar to 3.7 eV in the presence of the SnO and SnO, phases. Surface doping of nanolayers with palladium gave the Pd, PdO, and PdO2 components, among which PdO was most intense. Alternate treatments with O-2 and H-2 gases led to the disappearance of palladium dioxide and the reduction of PdO to the Pd metal. After the volume doping of nanoplayers with palladium, the surface layer contained PdO and PdO2; the latter was represented by two types of particles with different sizes.
Finding an abundant and cost-effective electrocatalyst for the hydrogen evolu-tion reaction (HER) is crucial for a global production of hydrogen from water electrolysis. This work reports an exceptionally large surface area hybrid catalyst electrode comprising semicrystalline molybdenum sulfi de (MoS 2+ x) catalystattached on a substrate based on nitrogen-doped carbon nanotubes (N-CNTs), which are directly grown on carbon fiber paper (CP). It is shown here that nitrogen-doping of the carbon nanotubes improves the anchoring of MoS 2+ xcatalyst compared to undoped carbon nanotubes and concurrently stabilizes a semicrystalline structure of MoS 2+ x with a high exposure of active sites for HER. The well-connected constituents of the hybrid catalyst are shown to facilitate electron transport and as a result of the good attributes, the MoS 2+ x/N-CNT/CPelectrode exhibits an onset potential of −135 mV for HER in 0.5 M H2SO4, a Tafel slope of 36 mV dec −1, and high stability at a current density of −10 mA cm −2.
The pressure evolution of RbBH4 has been characterized by synchrotron powder X-ray diffraction and Raman spectroscopy up to 23 GPa. Diffraction experiments at ambient temperature reveal three phase transitions, at 3.0, 10.4, and 18 GPa (at 2.6, 7.8, and 20 GPa from Raman data), at which the space group symmetry changes in the order Fm-3m(Z=4) → P4/nmm(2) → C222(2) → I-42m(4). Crystal structures and equations of state are reported for all four phases. The three high-pressure structure types are new in the crystal chemistry of borohydrides. RbBH4 polymorphs reveal high coordination numbers (CNs) for cation and anion sites, increasing with pressure from 6 to 8, via an intermediate 4 + 4 coordination. Different arrangements of the tetrahedral BH4 group in the Rb environment define the crystal symmetries of the RbBH4 polymorphs. The structural evolution in the MBH4 series is determined by the cation's size, as it differs drastically for M = Li (CNs = 4, 6), Na (CN = 6), and Rb. The only structure common to the whole MBH4 family is the cubic one. Its bulk modulus linearly decreases as the ionic radius of M increases, indicating that the compressibility of the material is mainly determined by the repulsive BH4···BH4 interactions.
The new mixed-valence octanuclear cobalt carboxylate complexes [CoII4CoIII4(μ4-O)4-(μ3-OMe)4(μ-O2CR)6(O2CR)2(H2O)6]·4H2O, where R = Et (3) or n-Pr (4), were investigated by X-ray diffraction analysis. Complexes 3 and 4 have a molecular octanuclear structure, and they are valence trapped, and contain four cobalt atoms Co3+ in the central cubane fragment with four cobalt atoms Co2+ at the periphery of the molecules. The molecules of the complexes are stabilized by four intramolecular hydrogen bonds and are linked, together with water solvent molecules, by intermolecular hydrogen bonds to form a three-dimensional supramolecular system.
Recently we demonstrated that the decavanadate (V-10) ion is a stronger Ca2+-ATPase inhibitor than other oxometalates, such as the isoelectronic and isostructural decaniobate ion, and the tungstate and molybdate monomer ions, and that it binds to this protein with a 1 : 1 stoichiometry. The V-10 interaction is not affected by any of the protein conformations that occur during the process of calcium translocation (i.e. E1, E1P, E2 and E2P) (Fraqueza et al., J. Inorg. Biochem., 2012). In the present study, we further explore this subject, and we can now show that the decaniobate ion, [Nb-10 = Nb10O28](6-), is a useful tool in deducing the interaction and the non-competitive Ca2+-ATPase inhibition by the decavanadate ion [V-10 = V10O28](6-). Moreover, decavanadate and vanadate induce protein cysteine oxidation whereas no effects were detected for the decaniobate, tungstate or molybdate ions. The presence of the antioxidant quercetin prevents cysteine oxidation, but not ATPase inhibition, by vanadate or decavanadate. Definitive V(IV) EPR spectra were observed for decavanadate in the presence of sarcoplasmic reticulum Ca2+-ATPase, indicating a vanadate reduction at some stage of the protein interaction. Raman spectroscopy clearly shows that the protein conformation changes that are induced by V-10, Nb-10 and vanadate are different from the ones induced by molybdate and tungstate monomer ions. Here, Mo and W cause changes similar to those by phosphate, yielding changes similar to the E1P protein conformation. The putative reduction of vanadium(V) to vanadium(IV) and the non-competitive binding of the V-10 and Nb-10 decametalates may explain the differences in the Raman spectra compared to those seen in the presence of molybdate or tungstate. Putting it all together, we suggest that the ability of V-10 to inhibit the Ca2+-ATPase may be at least in part due to the process of vanadate reduction and associated protein cysteine oxidation. These results contribute to the understanding and application of these families of mono-and polyoxometalates as effective modulators of many biological processes, particularly those associated with calcium homeostasis.
Over the last few decades there has been increasing interest in oxometalate and polyoxometalate applications to medicine and pharmacology. This interest arose, at least in part, due to the properties of these classes of compounds as anti-cancer, anti-diabetic agents, and also for treatment of neurodegenerative diseases, among others. However, our understanding of the mechanism of action would be improved if biological models could be used to clarify potential toxicological effects in main cellular processes. Sarcoplasmic reticulum (SR) vesicles, containing a large amount of Ca(2+)-ATPase, an enzyme that accumulates calcium by active transport using ATP, have been suggested as a useful model to study the effects of oxometalates on calcium homeostasis. In the present article, it is shown that decavanadate, decaniobate, vanadate, tungstate and molybdate, all inhibited SR Ca(2+)-ATPase, with the following IC(50) values: 15, 35, 50, 400 mu M and 45 mM, respectively. Decaniobate (Nb(10)), is the strongest P-type enzyme inhibitor, after decavanadate (V(10)). Atomic-absorption spectroscopy (AAS) analysis, indicates that decavanadate binds to the protein with a 1:1 decavanadate:Ca(2+)-ATPase stoichiometry. Furthermore, V10 binds with similar extension to all the protein conformations, which occur during calcium translocation by active transport, namely El, El P, E2 and E2P, as analysed by MS. In contrast, it was confirmed that the binding of monomeric vanadate (H(2)VO(4)(2-):V(1)) to the calcium pump is favoured only for the E2 and E2P conformations of the ATPase, whereas no significant amount of vanadate is bound to the E1 and E1P conformations. Scatchard plot analysis, confirmed a 1:1 ratio for decavanadate-Ca(2+)-ATPase, with a dissociation constant, k(d) of 1 mu M(-1). The interaction of decavanadate V(10)O(28)(6-) (V(10)) with Ca(2+)-ATPase is prevented by the isostructural and isoelectronic decaniobate Nb(10)O(28)(6-) (Nb(10)), whereas no significant effects were detected with ATP or with heparin, a known competitive ATP binding molecule, suggesting that V(10) binds non-competitively, with respect to ATP, to the protein. Finally, it was shown that decaniobate inhibits SR Ca(2+)-ATPase activity in a non competitive type of inhibition, with respect to ATP. Taken together, these data demonstrate that decameric niobate and vanadate species are stronger inhibitors of the SR calcium ATPase than simple monomeric vanadate, tungstate and molybdate oxometalates, thus affecting calcium homeostasis, cell signalling and cell bioenergetics, as well many other cellular processes. The ability of these oxometalates to act either as phosphate analogues, as a transition-state analogue in enzyme-catalysed phosphoryl group transfer processes and as potentially nucleotide-dependent enzymes modulators or inhibitors, suggests that different oxometalates may reveal different mechanistic preferences in these classes of enzymes. (C) 2011 Elsevier Inc. All rights reserved.
Diabetes mellitus is one of the most threatening epidemics of modern times with rapidly increasing incidence. Vanadium and peroxovanadium compounds have been shown to exert insulin–like actions and, in contrast to insulin, are orally applicable. However, problems with side–effects and toxicity remain. The exact mechanism(s) by which these compounds act are not yet fully known. Thus, a better understanding of the aqueous chemistry of vanadates and peroxovanadates in the presence of various (bio)ligands is needed.
The present thesis summarises six papers dealing mainly with aqueous speciation in different vanadate – and peroxovanadate – ligand systems of biological and medical relevance. Altogether, five ligands have been studied, including important blood constituents (lactate, citrate and phosphate), a potential drug candidate (picolinic acid), and a dipeptide (alanyl serine) to model the interaction of (peroxo)vanadate in the active site of enzymes. Since all five ligands have been studied both with vanadates and peroxovanadates, the number of systems described in the present work is eleven, including the vanadate – citrate – lactate mixed ligand system. The pH–independent formation constants have been determined for 33 ternary vanadate – ligand, 41 quaternary peroxovanadate – ligand and two vanadate – mixed ligand species in addition to the pKa values of all five ligands. These constants have been used to model physiological conditions, and the biomedical relevance of the different species is discussed.
The studies have been performed at 25 ºC in the physiological medium of 0.150 M Na(Cl), i.e. the ionic strength of human blood. No buffers have been used, and wide pH–ranges have usually been covered. The applied experimental techniques comprise mostly 51V NMR and potentiometry, but 31P, 13C, 1H and 14N NMR as well as EPR and ESI–MS have also been used to gain additional information. Multimethod data have been treated by the least–squares program LAKE and modelling has been carried out by the software package WinSGW.
Whenever possible, solution structures of the species have been proposed. In addition, simple biological tests have been carried out to determine the stability of the formed peroxovanadate complexes in the presence of human catalase. A brief comparison is given of the different vanadate – ligand and peroxovanadate – ligand systems with emphasis on observed trends and general features.
The bed agglomeration characteristics during combustion of phosphorus-rich biomass fuels and fuel mixtures were determined in a fluidized (quartz) bed reactor (5 kW). The fuels studied (separately and in mixtures) included logging residues, bark, willow, wheat straw, and phosphorus-rich fuels, like rapeseed meal (RM) and wheat distillers dried grain with solubles (DDGS). Phosphoric acid was used as a fuel additive. Bed material samples and agglomerates were studied by means of scanning electron microscopy (SEM) in combination with energy-dispersive X-ray spectroscopy (EDX), in order to analyze the morphological and compositional changes of coating/reaction layers and necks between agglomerated bed particles. Furthermore, bed ash particles were separated by sieving from the bed material samples and analyzed with SEM/EDS and powder X-ray diffraction (XRD). For logging residues, bark, and willow, with fuel ash rich in Ca and K but with low contents of P and organically bound Si, the bed layer formation is initiated by reactions of gaseous or liquid K compounds with the surface of the bed material grains, resulting in the formation of a potassium silicate melt. The last process is accompanied by the diffusion/dissolving of Ca into the melt and consequent viscous flow sintering and agglomeration. The addition of high enough phosphorus content to convert the available fuel ash basic oxides into phosphates reduced the amount of K available for the reaction with the quartz bed material grains, thus preventing the formation of an inner bed particle layer in the combustion of logging residues, bark, and willow. Some of the phosphate-rich ash particles, formed during the fuel conversion, adhered and reacted with the bed material grains to form noncontinuous phosphate−silicate coating layers, which were found responsible for the agglomeration process. Adding phosphorus-rich fuels/additives to fuels rich in K and Si (e.g., wheat straw) leads to the formation of alkali-rich phosphate−silicate ash particles that also adhered to the bed particles and caused agglomeration. The melting behavior of the bed particle layers/coatings formed during combustion of phosphorus-rich fuels and fuel mixtures is an important controlling factor behind the agglomeration tendency of the fuel and is heavily dependent on the content of alkaline earth metals in the fuel. A general observation is that phosphorus is the controlling element in ash transformation reactions during biomass combustion in fluidized quartz beds because of the high stability of phosphate compounds.
Samples with Mg1-xDxB2.04 (D = Pt, Pd or Re) nominal compositions have been synthesised by a solid-state route. None of these doping elements can be substituted for Mg in a detectable amount and their presence in the samples has no influence on the critical temperature and on the lattice parameters of the MgB2 superconductor. Impurity phases are formed by reaction mostly with Mg. The microstructure of the Pt, Pd and Re-based phases depends on the elements. Re-rich particles with large sizes up to 8 mu m form, whereas Pt- and Pd-containing impurities are finely dispersed with a particle size that does not exceed 1 mu m. The field dependence of the normalised critical current density is improved when Pt, Pd or Re are present in the samples. (C) 2015 Elsevier B.V. All rights reserved.
Since the first successful triol-functionalization of the Anderson polyoxometalates, the six protons of their central octahedron X(OH)6 (X—heteroatom, p- or d-element) have been considered as a prerequisite for their functionalization with tripodal alcohols, and therefore, the functionalization of Anderson structures from the unprotonated sides have never been reported. Here, we describe the triol-functionalization of [Cr(OH)3W6O21]6– leading to the single-side grafted anions [Cr(OCH2)3CRW6O21]6– (CrW6-tris-R, R = −C2H5, −NH2, −CH2OH) and the unprecedented double-side functionalized anion [Cr((OCH2)3CC2H5)2W6O18]3– (CrW6-(tris-C2H5)2), despite the lack of protons in the parent anion in the solid state. CrW6-(tris-C2H5)2 demonstrates the first example of double-side functionalized Anderson POT with the partially one-side protonated corresponding parent anion. The new heteropolytungstates were characterized by single-crystal X-ray diffraction, elemental analysis, Fourier-transform infrared spectroscopy, thermal gravimetric analysis, cyclic voltammetry, and electrospray ionization mass spectrometry. Density functional theory calculations were performed to investigate and compare the stability among the different isomers of the parent anion [Cr(OH)3W6O21]6–.
A C-linked analogue of β-d-galactosylthreonine has been prepared from 2,3,4,6-tetra-O-benzyl-d-galactopyranolactone (1) in 14 steps. Three stereogenic centers were created during the synthesis, with the anomeric center of the C-glycoside being generated first by addition of a Grignard reagent to 1 and subsequent reduction of the intermediate hemiacetal with triethylsilane. The two stereogenic centers in the threonine moiety were both established by alkylation of Evans' chiral N-acyloxazolidinone enolates.
The direct variable costs for heat and electricity production based on solid biomass fuel combustion is approximately 3-5 times lower than the costs in a fossil fuel-oil based boiler in Sweden. In addition waste derived biomass fuels are typically much cheaper than biomass not classified as waste. The introduction of the waste derived fuels; wastewater treatment sludge, demolition wood, and animal waste in a 50MWth circulating fluidized bed (CFB) biomass boiler located in Perstorp, Sweden, led to rapid deposit buildup in superheaters, heavy ash accumulation in economizers and failing boiler tubes and vortex finders that forced frequent boiler shutdowns. This in turn increased the use of expensive oil (fossil fuel) in backup boilers and the CO2 footprint of the on-site energy conversion system. This work aims to increase the general mechanistic understanding of combustion systems using complex fuels, and includes: A mapping of the boiler failure and preventive maintenance statistics; elemental composition analysis of ash, deposits and fuel fractions; flue-gas composition measurements; chemical speciation analysis; an attempt to describe the overall ash transformation reactions and mass balance throughout the combustion process. Scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) was used to analyze the elemental composition of ash and deposits. The SEM-EDS results were used together with data from X-ray powder diffraction (XRD) analysis, thermodynamic phase data, and equilibrium calculations in an attempt to quantify the crystalline phases and the overall ash transformation of the process. Based on the findings concerning ash transformation and the failure statistics, it has been possible to identify generic key parameters regarding boiler design and process parameters, enabling major improvements of the CFB boiler availability, a lower overall energy conversion cost and a reduced CO2 footprint.
Signal analysis in Nuclear Magnetic Resonance spectroscopy is among the most powerful methods to quantify reaction rates in aqueous solutions. To this end, the Swift-Connick approximations to the Bloch-McConnell equations have been used extensively to estimate rate parameters for elementary reactions. The method is primarily used for O-17 NMR in aqueous solutions, but the list of geochemically relevant nuclei that can be used is long, and includes Si-29, Al-27, F-19, C-13 and many others of particular interest to geochemists. Here we review the derivation of both the Swift-Connick and Bloch-McConnell equations and emphasize assumptions and quirks. For example, the equations were derived for CW-NMR, but are used with modern pulse FT-NMR and can be applied to systems that have exchange rates that are shorter than the lifetime of a typical pulse. The method requires a dilute solution where the minor reacting species contributes a negligible amount of total magnetization. We evaluate the sensitivity of results to this dilute-solution requirement and also highlight the need for chemically well-defined systems if reliable data are to be obtained. The limitations in using longitudinal relaxation to estimate reaction rate parameters are discussed. Finally, we provide examples of the application of the method, including ligand exchanges from aqua ions and hydrolysis complexes, that emphasize its flexibility. Once the basic requirements of the Swift-Connick method are met, it allows geochemists to establish rates of elementary reactions. Reactions at this scale lend themselves well to methods of computational simulation and could provide key tests of accuracy. (C) 2011 Elsevier Ltd. All rights reserved.
We have synthesized and characterized the monomeric diiminophosphinate-stabilized Group 13 metal(I) complexes [DipLE:], DipL=Ph2P(NDip)2, Dip=2,6-iPr2C6H3; E=Ga (1), In (2) and Tl (3). In addition, we structurally characterized the dimeric complex [(DipLGa)2], 12. Similar synthetic attempts using MesL=Ph2P(NMes)2, Mes=2,4,6-Me3C6H2 afforded product mixtures from which the mixed oxidation state species [(MesL)3Ga4I3] 4 was isolated. [DipLGa:] 1 is converted with dry air to the gallium(III) oxide species [(DipLGaO)2] 5. Density Functional Theory studies on [DipLE:] and [(DipLE)2], E=Al−Tl, shed light on the bonding in these compounds and show that the newly formed E−E bonding interactions can be described as weak single σ-bond with no significant π-bonding contribution for E=Al, Ga. A large contribution to the dimer binding enthalpies results from London dispersion forces.
Reducing the global dependence on fossil fuels is of paramount importance in tackling the environmental challenges we face, not only tomorrow, but already today. Biomass offers a renewable supply of CO2-neutral raw material that can be converted into many different forms of fuels and valuable chemicals, making it a prime candidate for the technologies of tomorrow. However, the heterogeneous nature and distinctly different elemental composition of biomass compared to traditional fossil sources present new challenges to be solved. When it comes to thermochemical technologies, key issues concern fuel conversion efficiency, ash formation, ash/fuel interactions and ash/reactor material interactions.
The objective of the present thesis was to provide new knowledge and insights into thermochemical fuel conversion, in particular its application in entrained flow technologies. A laboratory-scale reactor was constructed, evaluated and was used to study several aspects of high-temperature entrained flow biomass fuel conversion. Pulverized fuel particles from different biomass sources were used, and their physical and chemical interactions with the surrounding atmosphere, the concurrent ash element release, ash formation, and phase interactions were also studied in detail. In addition to the entrained flow reactor designed and constructed for this purpose, the main method for data collection was in situ optical studies of converting particles, either while entrained in the flow or when impacting upon surfaces. Elemental composition analysis of collected samples and gas analysis were also performed, allowing for a deeper understanding of ash element fractionation and interactions and thus explaining the observed properties of the resulting deposits or slag.
The degree of conversion of fuels with very low ash content, such as stem wood, was well described and modeled by a novel method using optical data, offering a non-intrusive and non-destructive alternative to traditional techniques. Coupling computational fluid dynamics with optical data allowed for improved experimental data interpretation and provided improved accuracy for fuel particle residence time estimations, which is an important parameter when studying fast chemical reactions such as those taking place in reactors for entrained flow conditions. The results from studies on ash formation gave new insights into the feasibility of using dry-mixed K-rich additives for improving slag properties during gasification of Ca-rich and Si-rich fuels. Interpretations of the experimental results were supported by thermodynamic equilibrium calculations, and the conclusions highlight both possibilities and challenges in gasification with high fuel flexibility while at the same time producing a flowing slag. Applications and future implications are discussed, and new topics of interest are presented.
Managing slag properties is of utmost importance for successful operation of entrained flow gasifiers. The present study details some aspects of slag formed from a softwood bark fuel, and especially the situation with only small amounts of mineral contaminants, meaning composition is shifted from Si- towards P-dominated ash. Wood bark with and without KHCO3 additive was gasified between 850 °C and 1300 °C at O2 stoichiometric ratio (λ) 0.6 to study the resulting ash properties and the influence of the additive. The ash particles collided with a flat impact probe inside the hot reactor, with particle impact angles varied between 90° to 30°. The reactor and probe were constructed to allow for long-distance microscope data collection close to the surface of the probe. In situ PIV and SEM-EDS of deposit samples from lab scale entrained flow gasification experiments were used for evaluation, while XRD was used to characterize carbonates. High potassium release was found but numerous spherical ash particles indicated lower ash melting temperatures than expected from the bulk ash composition. These new findings propose a mechanism for melt formations involving carbonates rich in potassium and phosphorous, followed by K-release and calcination leading to solidification.
In many northern temperate regions, the water color of lakes has increased over the past decades (lake browning), probably caused by an increased export of dissolved organic matter from soils. We investigated if the increase in water color in two lakes in Norway has resulted in increased burial of organic carbon (OC) and mercury (Hg) in the sediments and if the Hg was prone to methylation. Lake Solbergvann experienced a threefold water color increase, and OC burial increased approximately twofold concomitant to the water color increase. This lake had prolonged periods of anoxic bottom water, and anoxic OC mineralization rates were only about half of the oxic OC mineralization rates (7.7 and 17.5g C m(-2)yr(-1), respectively), contributing to an efficient OC burial. In Lake Elvaga, where water color increase was only approximately twofold and bottom water was oxygenated, no recent increase in OC burial could be observed. Hg burial increased strongly in both lakes (threefold and 1.6-fold in Lake Solbergvann and Lake Elvaga, respectively), again concomitant to the recent water color increase. The proportion of methylated Hg (MeHg) in surficial sediment was 1 order of magnitude higher in Lake Elvaga (up to 6% MeHg) than in Lake Solbergvann (0.2-0.6% MeHg), probably related to the different oxygenation regimes. We conclude that lake browning can result in increased OC and Hg burial in lake sediments, but the extent of browning and the dominating mode of sediment respiration (aerobic or anaerobic) strongly affect burial and fate of OC and Hg in sediments.
The electronic structure and magnetic states in the heterometallic hexanuclear complex Mn4II Fe2III (μ4-O)2(Piv)10 · MeCN4 have been studied by X-ray photoelectron spectroscopy (XPS). The substitution of two Mn atoms for two Fe atoms in the hexanuclear complex was found to have an effect on the patterns of iron and manganese X-ray photoelectron spectra. XPS data are evidence of the high-spin paramagnetic state of MnII and FeIII atoms, as well as of the ligand-metal charge transfer upon complex formation. In the heteroatomic complex, the degree of bond covalence increased for both the manganese and iron atoms. The results obtained are in good agreement with X-ray diffraction data.
Binuclear pivalate complexes of 3d transition metals (manganese, iron, cobalt, and nickel) with the same ligand environment and a lantern structure have been studied by X-ray photoelectron spectroscopy. The M2p, M3s, C1s, O1s, and N1s X-ray photoelectron spectra have been examined. A redistribution of electron density in the OCO group has been revealed. It has been shown that the theory fits the experimental data on the energy separation between the high- and low-spin components in the M3s spectra and between the spin doublet components in the M2p spectra. It has been demonstrated that the iron, cobalt, and nickel complexes are paramagnetic at room temperature, whereas the manganese complex exhibits antiferromagnetic properties. There is a correlation between the size of the 3d subshell of the transition metal atom and the M-O and M-N bond lengths.
Rates of oxygen-isotope exchange were measured in the tetrasiliconiobate ion [H2+xSi4Nb16O56]((14-x)-) to better understand how large oxide ions interact with water. The molecule has 19 nonequivalent oxygen sites and is sufficiently complex to evaluate hypotheses derived from our previous work on smaller clusters. We want to examine the extent to which individual oxygen atoms react independently with particular attention given to the order of protonation of the various oxygen sites as the pH decreases from 13 to 6. As in our previous work, we find that the set of oxygen sites reacts at rates that vary over approximately 104 across the molecule at 6 < pH < 13 but with similar pH dependencies. There is NMR evidence of an intra-or intermolecular reaction at pH similar to 7, where new peaks began to slowly form without losing the O-17 isotopic tag, and at pH <= 6 these new peaks formed rapidly. The oxygen atoms bonded to silicon atoms began to isotopically exchange at pH 9 and below. The 17O NMR peak positions also vary considerably with pH for some, but not all, nonequivalent oxygen sites. This variation could be only partly accounted by electronic calculations, which indicate that oxygen atoms should shift similarly upon protonation. Instead, we see that some sites change enormously with pH, whereas other, similarly coordinated oxygen atoms are less affected, suggesting that either some protons are exchanging so rapidly that the oxygen sites are seeing an averaged charge, or that counterions are modulating the effect of the coordinated protons.
N-(phosphonomethyl)glycine (glyphosate, PMG) is the most widely used herbicide, and its adsorption onto soil minerals plays a significant role in its mobility and rate of degradation. In this work, we present the results of the first serious effort to find a realistic surface complexation model that fits both adsorption and total proton concentration data for PMG on the common soil mineral, goethite. Special attention was focused on making sure that the final model was in good semiquantitative agreement with previously reported X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopic measurements. Electrostatic effects were accounted for using the Basic Stern model, and the charges of the PMG-containing surface complexes were assumed to be distributed across the 0- and β-planes. The reactions for the protonation of the goethite surface were described using the 1 pK model. We optimized on the intrinsic formation constants and the charge distributions of the complexes, as well as the initial total proton concentration (I = 0.1 M Na(NO3), 25.0 °C), and the following model was obtained.
Here, β is the intrinsic formation constant, Q0 is the charge at the 0-plane, and the errors are reported as one standard deviation. The charge distributions of the complexes are rationalized by considering intramolecular hydrogen bonding between the protons of the amine group and both the phosphonate and carboxylate groups.
The mining of sulphidic ore to extract metals such as zinc and copper produces huge quantities of waste material. The weathering and oxidation of the waste produces what is commonly known as Acid Mine Drainage (AMD), a dilute sulphuric acid rich in Fe(II) and heavy metals. This thesis serves to summarise five papers reporting how the precipitation of Fe(III) phases can attenuate the contamination of heavy metals by adsorption processes.
Schwertmannite (Fe8O8(OH)6SO4) is a common Fe(III) mineral precipitating in AMD environments at pH 3-4. The stability and surface chemistry of this mineral was investigated. It was shown that the stability depended strongly on pH and temperature, an increase in either promoted transformation to goethite (α-FeOOH). Two pH dependent surface species of SO42- were detected with infrared (ATR-FTIR) spectroscopy.
The adsorption of Cu(II), Pb(II) and Zn(II) to schwertmannite occurred at lower pH than to goethite, whereas Cd(II) adsorption occurred in a similar pH range on both schwertmannite and goethite. Extended x-ray absorption fine structure (EXAFS) spectroscopy suggests two surface species for Cu(II) and Cd(II) at the schwertmannite surface. Cu(II) adsorbs monodentately and Cd(II) bridging bidentately to adsorbed SO42-. Both metal ions also adsorb in a bridging bidentate mode to the surface hydroxyl groups. At pH 7.5 up to 2.7 μmol Cd(II) m-2 could be adsorbed to schwertmannite, indicating a large adsorption capacity for this mineral.
The acid-base properties of two NOM samples were characterised and could be well described as diprotic acids below pH 6. The adsorption of NOM to schwertmannite and goethite was very similar and adsorption occured in a very wide pH range.
High concentrations of NOM increased the adsorption of Cu(II) to goethite at low pH whereas a slight decrease was noted at low concentrations of NOM. No effect was detected in the schwertmannite system.
The formation of Fe(III) phases from precipitation of AMD was shown to be very pH dependent. At pH 5.5 a mixture of minerals, including schwertmannite, formed whereas at pH 7 only lepidocrocite (γ-FeOOH) formed. The concentration of Zn(II) in AMD could by adsorption/coprecipitation be reduced to environmentally acceptable levels.
The structure of palladium(II) ethylenediaminetetraacetate (edta) in aqueous solutions and its adsorption on the surface of goethite (-FeOOH) were studied using extended X-ray absorption fine structure spectroscopy and attenuated total reflection Fourier transform infrared spectroscopy. The obtained results show that in aqueous solutions, Pd-edta exists as a 1:1 complex, [Pd(edta)]2-, with edta acting as a quadridentate ligand. On the surface of goethite, [Pd(edta)]2- forms two different types of complexes over a pH range of 3.40-8.12. At pH < 5, [Pd(edta)]2- adsorbs as an outer-sphere species with possible hydrogen bonding. At higher pH values, the formation of inner-sphere complexes of the cation-type sets in after a cleavage of one glycinate ring and the formation of an (edta)Pd-O-Fe linkage.
The organic horizon (the mor layer) of podzolized boreal forest soils has accumulated atmospheric fallout of mercury and lead over centuries, resulting in current concentrations close to levels where negative effects on soil biota are thought to occur. To what extent the pollution history is preserved in the stratigraphy of this horizon is not well known. In this study we asses whether the chronology of a large historic pulse of atmospheric pollution emitted from the Ronnskar smelter in northern Sweden, particularly between 1950 and 1980, is preserved within the stratigraphy of the mor layer, which is typically 5-cm thick. Vertical sub-sampling (<= 5 mm) of five mor profiles sampled along a 100-km pollution gradient away from the smelter are analyzed for mercury and lead concentrations, spheroidal carbonaceous particles from fossil fuel combustion (SCPs) and stable lead isotopes (Pb-206/Pb-207 and Pb-208/Pb-207). Their vertical distribution is compared with the temporal variations in atmospheric inputs reconstructed for the last similar to 100 years from analyses of an ombrotrophic peat core and a varved take sediment core sampled within a distance of 50 km of the smelter. The mor profiles situated <= 12 km from the smelter record the pollution history of the smelter. There is a 20 to 40-times enrichment of Hg, Pb and SCP at the transition in the O-horizon from the F- to H-layer compared to the basal part and a distinct peak in the Pb-206/Pb-207 ratio (similar to 1.22) in the F-layer. The mor profiles situated outside the historical contamination range of the smelter (80 and 100 km away) record no obvious influence from the Ronnskar smelter, instead their vertical Pb-206/Pb-207 profiles follow the general regional pollution history in northern Sweden. We conclude that the mor layer preserves a record of atmospheric Hg, Pb and SCP inputs and due to low leaching rates this organic horizon serves as a semi-archive of atmospheric Hg and Pb pollution. We stress the need of including this property in the existing 'black-box' models predicting the fate of Hg and Pb within contaminated boreal forest soils.
A homologous family of low‐coordinate complexes of the formulation trans‐[M(2,2′‐biphenyl)(PR3)2][BArF4] (M=Rh, Ir; R=Ph, Cy, iPr, iBu) has been prepared and extensively structurally characterised. Enabled through a comprehensive set of solution phase (VT 1H and 31P NMR spectroscopy) and solid‐state (single crystal X‐ray diffraction) data, and analysis in silico (DFT‐based NBO and QTAIM analysis), the structural features of the constituent agostic interactions have been systematically interrogated. The combined data substantiates the adoption of stronger agostic interactions for the IrIII compared to RhIII complexes and, with respect to the phosphine ligands, in the order PiBu3>PCy3>PiPr3>PPh3. In addition to these structure–property relationships, the effect of crystal packing on the agostic interactions was investigated in the tricyclohexylphosphine complexes. Compression of the associated cations, through inclusion of a more bulky solvent molecule (1,2‐difluorobenzene vs. CH2Cl2) in the lattice or collection of data at very low temperature (25 vs. 150 K), lead to small but statistically significant shortening of the M−H−C distances.


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On Tuesday, level two restrictions were enacted in the capital of New South Wales (NSW), a state 99.9% in drought.
These could be increased to level three within months, local media report.
Temperatures are predicted to soar above 40C (104F) from Tuesday, worsening fires which have already killed six people since October.
There are now more than 100 fires in NSW and Queensland states, many of which have been burning for several weeks.
What are the water restrictions?
A second woman was found dead inside an apartment building on the same street.
"All the information we have at hand would link these two crimes," police commissioner Mick Fuller said at a press conference.
He said the suspect was a "lone actor" with a history of mental health issues.
He was known to police but "his history was unremarkable compared to the gravity of the crimes he committed", Mr Fuller said.
The police commissioner said the suspect had some ideologies related to terrorism, but had no apparent links to other terrorist organisations.
The event will be attended on PNG's behalf by the Chief Justice, Sir Gibbs Salika, and Deputy Speaker of Parliament Jeffrey Komal, and Acting PNG High Commissioner to Australia, Sakias Tameo.
They will be accompanied by other Pacific Islands Nation dignitaries to attend the event which aims to promote peace around the world.
It is forecast to reach 33 degrees Celsius in Sydney city, and 40C in western suburbs.
On Sunday, a reading of 47.3C was recorded in Penrith by the late afternoon, making it the hottest temperature recorded in Sydney since 1939. It was also the hottest city on Earth.
The Australian and England cricket teams suffered temperatures in the 50s out on the field at the Sydney Cricket Ground.
England captain Joe Root was taken to hospital to be treated for severe dehydration.
Similar rallies are being held in Brisbane and Melbourne as thousands of people stand in solidarity with the refugees.
According to the Refugee Action Coalition, authorities began removing the perimeter fencing of the detention centre late yesterday afternoon (Thursday 9 Nov), leaving the refugees even more vulnerable.
"Overnight a new notice was distributed in Port Moresby, where over 120 Manus refugees and asylum seekers being held, has made it obvious there are no plans for providing permanent resettlement," says spokesman Ian Rintoul.
Vivid transforms landmarks across the city using light, colour and sounds and attracts hundreds of thousands of visitors each year.
But making the spectacle accessible for people with limited or no vision is a challenge, particularly when it comes to what is arguably the highlight of the show, the lighting of the sails at the Opera House.
For the first time, films that have been made and acted by people living with disabilities will be a key part of the program.
It has been made possible by Screenability — an arts initiative in New South Wales to help more people with disabilities break into the film industry.
"I think it's really important that you have creatives with disability in charge of that narrative," Sydney Film Festival's Screenability programmer Sofya Gollan said.
It was a controlled start for both teams in the opening minutes of the first half.
The Kukis looked to have registered the first points as early as the sixth minute when David Munro grounded a deflected Isaac John grubber.
But the try was disallowed after the Bunker ruled Munro offside.
Two consecutive penalties brought the Kumuls out of their own half and within striking distance 10 metres out from their opponent's try line.
"Chinese people like whitening, [they consider it] beautiful — whitening and brightening because it's good," she says, smiling.
The smile is genuine, as Amanda is a fan herself.
"I use this one in the morning and at night … it can make your skin look very healthy, very clear," she says.
"It's very popular."
And this popularity is on the rise with the market for skin lighteners projected to reach $US23 billion ($30.5 billion) by 2020, according to market intelligence firm Global Industry Analysts.
Ben McCormack, 42, a well-known reporter for the local A Current Affair programme, was arrested in Sydney.
Police searched an apartment and the offices of his employer, the Nine Network, seizing computers, a mobile phone and an electronic storage device.
The Nine Network immediately suspended Mr McCormack from his reporting duties.
Police released images of Mr McCormack's arrest, showing his face blurred, and charged him with using a carriage service for child pornography material.

subset: commoncrawl


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23 Jan 2018 07:55
E and E Towing Providers gives towing for Tampa and close by areas. While most fashionable manufacturers design their automobiles the ways in which they're purported to final for several a long time even when topic to lively and steady use, some driving habits and omitted maintenance routines may impair the efficiency and the security of your vehicle, as well as lower its lifespan.We notice there are a number of companies on the internet which can buy your aged rubbish motorized vehicle; alternatively we wished to can help you know that this firm is just 5 years outdated and it has already been shopping for and promoting automobiles or vans all through the United States Of America.The significant reduction in expenses this sort of deal characterize versus a purchase order - with the leasing firm typically taking care of things reminiscent of insurance and maintenance for the car - means these women and men are in a position to aim significantly greater, model-wise, than they might in any other case have been.A few of these corporations are going to concentrate on certain facets of junk elimination, such as taking care of unused gadgets within the residence or perhaps specializing in building debris removing. Benefits from these automobiles should not only restricted and directed to automobile owners as a result of some benefits may also be gained by those people who don't have vehicles.Regardless of how common or seemingly worthless the remaining salvageable components to your "junker" might sound, there is all the time is perhaps someone on the market who will take it off your fingers at a cut price worth. Some models have patented features that can delay the life of a battery as much as 3 instances that of its regular lifespan.There is a tendency for this to occur with efficiency autos and that is why, potential purchasers have to be further cautious. Here's more info regarding sell junk car memphis look at the website. There aren't any rules stating that a seller has to disclose all the details about the autos being offered, the truth that these vehicles have been cleared from a salvage title must be info enough.The battery supplies the power required in working the auto's totally different electronics and units when the engine is turned off. Ensure you have those essential paperwork in hand before calling a scrap auto removing service. Scrap auto rates typically fluctuate depending on the ongoing scarp charges. Thus, ensure to verify a couple of days earlier than you intend to promote your unwanted automobile.The automobile battery supplies the power necessary to run the vehicle's electronics when the engine is shut off. You sell my junk car jacksonville fl probably have a junk car, truck, SUV, or van, all you must do is to search a nearby junk automobile towing service and may call them sell junk car memphis to select up your scrap automobile. At Junkacar the most typical destiny for salvage vehicles is to be actually recycled.


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Conservation, Events, News,
TULSA, Okla. (April 8, 2019)– Sip to save species from 6:30 to 9 p.m. on Friday, April 26, during the Tulsa Zoo's second annual brew event, Conservation on Tap.
This year, 100 percent of the proceeds from Conservation on Tap will benefit the Mabula Ground-Hornbill Project, a non-profit 501(c)(3) dedicated to the study and re-establishment of Southern ground-hornbills in South Africa.
Craft beer fans will enjoy a wide variety of tastings from 25 of Oklahoma's finest breweries and distributors, as well as other libations, including hard cider and non-alcoholic beverages.
Guests will wander the Lost Kingdom after hours, savoring 2-ounce samples while exploring the new exhibit complex. Live music, yard games and animal encounters will entertain patrons, while sweet and salty treats, available for purchase, will satisfy appetites.
"It was wonderful to witness our first Conservation on Tap event raise over $15,000 to help save wild chinchillas," said Jarrod Wyatt, Special Projects Manager. "The Tulsa Zoo was thrilled with our community's engagement and the opportunity to showcase some amazing local breweries and distributors. We are eager to continue that momentum on April 26th in support of the crucial Mabula Ground-Hornbill Project. It will undoubtedly be another special evening in our Lost Kingdom exhibit complex featuring some of the best brews from around the region and support efforts to save this remarkable and charismatic bird."
The Mabula Ground-Hornbill Project is dedicated to the conservation of Southern ground-hornbills in South Africa. For two decades, they have been working to save the species with outreach programs in schools and communities, field research, breeding, and a reintroduction program. Southern ground-hornbills are listed as Vulnerable by the International Union for Conservation of Nature. Within South Africa, the species is classified as Endangered by the ICUN due to habitat destruction, loss of nesting trees and secondary poisoning.
"The Tulsa Zoo has supported the Mabula Ground-Hornbill project by purchasing satellite transmitters that are essential for the reintroduction project," said Tulsa Zookeeper Seana Flossic. "There are only about 1,500 Southern ground-hornbills left in South Africa. They live in social, cooperative breeding groups, with only the alpha male and one breeding female laying eggs. The rest of the group are helpers. This means there are only about 400 breeding groups in all of South Africa. Data from this project shows that, on average, only one chick is raised to adulthood every nine years. Thus, every chick is invaluable and the transmitters help monitor the birds after release. Everyone who attends Conservation on Tap, or purchases a glass, is helping save this big, booming, beautiful bird."
Conservation on Tap is a 21-and-up event. General tickets are $45 and include admission, 2-ounce samples, commemorative 5-ounce tasting mug and lanyard. Designated Driver tickets are available for $20. Those unable to attend the event can still support the project by purchasing a limited edition 16-ounce commemorative beer glass for $20, including shipping.
A limited number of $65 VIP tickets are available for purchase that include all general admission amenities plus early entry at 6 p.m., food vouchers and a special take-away item.
Special thanks to Lanyard Sponsor: Ranch Acres Wine & Spirits for their support.
This event would not be possible without the participation from the following breweries, distributors and home brewers: American Solera; Angry Scotsman Brewing; Anthem Brewing; Bricktown Brewery, Broken Arrow Brewing Company; Cabin Boys Brewery; COOP Ale Works; Dead Armadillo Craft Brewing; Eerie Abby Ales; Fellowship of Oklahoma Ale Makers (FOAM); Iron Monk Brewing Company; LDF Companies, Inc.; Marshall Brewing Company; Mike's Hard Lemonade; New Belgium Brewery; New Era: Fine Fermentations; Nine Band Brewing at Osage Casino; Nothing's Left Brewing Company; OK Cider Co.; Pippin's Taproom at High Gravity Brewing Company; RAK Home Brew; Renaissance Brewing Company; Vanessa House Beer Company; Republic National Distributing Company serving Anchor Brewing, Dustbowl Brewing, Hard Frescos, John Daly, Rahr & Sons Brewing, and Unibroue; Southern Glazer's Wine and Spirits of Oklahoma serving Avery Brewing, Benediktiner, Estrella Damm, Founders Brewing, Great Divide Brewing, Kronenbourg Brewery, Left Hand Brewing, Lost Coast Brewery, and North Coast Brewing.


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Acne is a problem that affects millions of people all over the world. It can be caused by so many things like hormone imbalances or just improper cleansing. It also has a habit of appearing at just the wrong times like when you have a date or job interview. So with it affecting so many people, there just has to be an easy solution, right?
Well unfortunately not. If you take a look in your local pharmacy you will see a whole range of different products to help to treat acne. Everything from pills and potions are available and it's almost impossible to know what to choose that will help to rid your acne.
So let's look at one of the main reasons why acne occurs to help you understand how to treat it better.
The main cause of acne is generally dead skin cells that will clog up your pores. So the best treatment for acne is to remove these dead skin cells as best you can. This is done by regular cleaning with a product that works. One such product is called Acnezine. The Acnezine solution helps not only to treat acne you have but also to stop it from coming back in the future.
By using a product like Acnezine on a regular basis, you can give yourself a better chance that an outbreak of acne won't occur just when you don't want it to. The topical solution will help to keep your pores from being clogged and will in turn stop acne from returning.
Acnezine is popular all over the world and they have risk free trials and even free bottle offers at their website. So why not try Acnezine today and you will be amazed at the results and never have to worry about getting outbreaks of acne ever again.


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These cards are shipped in quantities of 50.
4x6 cards with a glossy front. Choose the message of hope you want to share with others. They are a great size for personal affirmation cards that students can collect through a campaign. The blank matte finished backs allow you to write or print personal messages of hope.
We all need encouragement now and then and these are the perfect size to encourage your beauticians, pastors, teachers and baristas.
Choose your message of hope:
- You Are Not Alone
- Your Mistakes Don't Define You
- Your Story is Still Being Written
- Your Life Matters
- There is Hope
- One Day at a Time
- Life has Seasons and Seasons Change
- Comparison is the Thief of Joy
- Dwell on the Beauty of Life
- Don't Give Up


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New program aims to improve truancy rates in Callaway County
Related Story
FULTON - Educators in Callaway County identified a total of 140 students from four middle schools who missed more than 17 days of school this year.
A new program, Working to Inspire Student Education (WISE), aims to address the problem without sending the students to juvenile court. Fulton, New Bloomfield, North and South Callaway middle schools will work with the Family Court and Juvenile Office of Callaway County and William Woods University to address the attendance issue.
"Absence and truancy is a really big deal and when kids aren't at school, they aren't learning and then it also sets up habits that will then affect them after school," said Beth Houf, principal at Fulton Middle School.
Houg said she has some students who have missed up to 50 school days.
"What we want to do is address the needs of school attendance and school performance through collaboration among our agencies without necessarily having to have these youth be referred to the juvenile court or be under a formal supervision," said Ruth McCluskey, chief juvenile officer for the 13th Circuit.
13th Judicial Circuit Juvenile Court Judge Sue Crane approached Cynthia Kramer, a professor of legal studies at William Woods University, asking if she would be interested in partnering with the court system.
"Of course we said yes because it provides so many neat opportunities for our students here at William Woods University," said Kramer. "William Woods University will provide support for those students so for example our education students, and social work students might work with those students in regard to what some of those problems might be and then our legal studies and criminal justice students will be be advocates and work in the operation of the court room."
Although it's not a real court, it will operate like one.
"When they get here, this will be operating just like a regular courtroom will. So everyone's going to sit down out there, there will be a bailiff, there will be 'all rise'," said Kramer.
Program organizers say the goal is not to scare students, but to get them back in class.
"It's not a gotcha it's more to me as a mentoring. William Woods is such an awesome partner and bringing students in to help mentor students and then just teach some replacement behaviors of what can we do to get students to school so that then it's so much more than just what's happening within middle school, it's beyond," said Houf.


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The German Plutonium Balance for the Years 1968-1999.
Reprocessing, Import and Export, MOX Fuel Elemement Production and Usage, Stored Inventories
Martin B. Kalinowski, Wolfgang Liebert, Silke Aumann
December 2002
57 pages
ISBN: 3-933071-05-4, Price $ 20, airmail shipping $ 10 extra
This technical report provides a comprehensive analysis of open-source information on plutonium inventories owned by German nuclear operators for the years 1968-1999. This survey includes plutonium separated by reprocessing of spent fuel in the Karlsruhe, Germany, reprocessing facility (Wiederaufarbeitungsanlage Karlsruhe or "WAK"), as well as at the La Hague reprocessing plant, in France, and the Sellafield reprocessing plant, in the United Kingdom; discusses import and export of unirradiated plutonium; and gives an overview of the past production of uranium-plutonium mixed oxide (MOX) fuel, as well as the usage of MOX fuel in Germany. The study presents these data on an annual basis since the end of the 1960s, although a number of uncertainties remain. As of the beginning of 1999, the study concludes, 23 to 30 tonnes of unirradiated (separated or in fresh MOX fuel) plutonium were under German control and responsibility in Germany or abroad. An additional 47 to 60 tonnes were still contained in spent fuel. However, because separated plutonium poses significant proliferation risks and because the German MOX program will have difficulty absorbing the country's existing stocks of this material, the future Germany's reprocessing program has been placed in doubt, and new initiatives are urgently needed to develop a comprehensive long-term strategy for addressing Germany's plutonium surpluses.
Table of Content:
Martin B. Kalinowski worked with IANUS and INESAP until 1998 and with the Preparatory Commission for the Comprehensive Nuclear Test-Ban-Treaty Organization (CTBTO) until 2006. Since 2006, he is Chair of the Carl Friedrich von Weizsäcker Centre for Science and Peace Research (ZNF) of the University of Hamburg; martin.kalinowski[at]uni-hamburg.de
Wolfgang Liebert is Scientific Director of the Interdisciplinary Research Group Science, Technology and Security of Technische Universität Darmstadt; liebert[at]ianus.tu-darmstadt.de.
Silke Aumann worked with IANUS until 1998.
To order a Technical Report, please send your order to:
INESAP c/o IANUS
Technische Universität Darmstadt
Hochschulstrasse 4a
D-64289 Darmstadt, Germany
The Order will be mailed to you as soon as your payment has been received either:


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May 15th, 2004, 12:55 PM #1
Dads Facing the Dawn of a New Era
Facing the Dawn of a New Era
By Mark Stackpole
Dads may get relegated to the background when Baby arrives, but this new dad shares some tips to make yourself useful.
A new age has dawned. A new era has begun. Your old life is now as extinct as a dinosaur or VHS. As a father, you must get used to a certain sense of obsolescence. Due to your biological inability to feed your baby, she barely notices that you are around. (As I have daughter, all baby pronouns will be in the feminine form.) You'll get a token look because of your deep voice, which also happens to cause a startle response and instant tears. Great. (My own beloved daughter actually bursts into tears whenever I start to sing to her, which proves that she has great taste in music, but still hurts my feelings.)
The baby's mom will be pretty caught up in the intense relationship between herself and the new baby - bonding, breastfeeding and more. As for the way that everyone else thinks about you, get used to the fact that you now fall somewhere between "piece of furniture" and "beast of burden."
There's little glory in being the father of a newborn. It's a good thing that you love her so much that you barely notice. Of course, due to the lack of sleep, there are a lot of other things that you barely notice - red lights, football games - well, you get the point.
In the spirit of thinking so that you don't have to, I have put together a few things that I think new fathers need to learn. Bear in mind that since my own daughter is 5 weeks old, I am something of an expert. Surely I will be able to apply what I have already learned to the next 18 years or so of our respective lives.
For starters, fathers, you might be wondering how to clean baby puke off of your golf shirt. Well, let me break this to you gently. You don't. Get a new shirt. A cheap one. It's not like you are going to have the time to golf anyway. Maybe in a couple of years I will see you by the windmill at the Pitch and Putt with the kids. Until then, your new tee time is "never o'clock."
You may also be asking the question, "How does such a big smell come from something so small that only drinks milk?" Well, it just does. Accept it and move on. And if you have to change a diaper that weighs more than the baby herself, grab some goggles, gloves, a hose and some wipes. Go with God, my friend. And pray for the scent-deadening joy of a sinus infection.
On a related note, I have often wondered how far to pull those little diaper tabs before I am cutting off the circulation to the baby's lower extremities. As near as I have been able to tell, cute pink toes are good. Alarming purple ones, bad. You don't want that diaper coming loose and falling off, but better her diaper falls off than her left leg. Take some comfort in the fact that your wife will critique your efforts in this department, leading to your eventual humiliation, but ensuring the safety of the child.
The biggest assault that a new father's ego must withstand, however, is the simple fact that no one really wants to see him anymore. A typical greeting when you visit friends and relatives is something like, "Mom looks so great. The baby is so beautiful. And Dad - thanks for driving the car that brought them over so we could see them."
The experience is only marginally different when people come over to your house, with the conversation consisting of something like, "Where's the baby? How's Mom? And Dad, while you're up, could you get me a soda?" (It is important to note that the last question gets asked regardless of whether or not you are actually "up" at that particular time.)
But you are fighting the good fight and want to do the best thing for your baby. Since you haven't yet been able to establish the same bond as your wife, you are anxious to do anything you can to please her. The simple answer to the question is this: If you really want to please your baby, go get Mom. You might get a brief smile, but Mom's got the goods.
Let me close by offering you a few tips on how to actually be useful during the time between your child's birth and her ability to appreciate what a cool dad you are.
1. Are you familiar with the pack mule? Never seen one before? Look in the mirror.
2. Cook dinner for your exhausted wife. Or, if she doesn't like canned pasta, go pick something up.
3. Change diapers. Sure, it's the smelliest bonding experience since you and your college buddies used to, well, never mind what you guys used to do. You're a father now, for crying out loud. Grow up. You ought to be ashamed of yourself. But, ah, the memories. Regardless of your sordid past, I am not kidding about the bonding experience. My daughter and I have had some of our best conversations while changing her pants. We look each other in the eyes and talk. Don't deprive yourself. Stop laughing. I'm serious. Really. Seriously. OK, you're still laughing, but I am going to move onto the conclusion. But I'm really seriously really serious. You still don't believe me, do you? I'm right, but let's move on.
There is nothing quite like becoming a co-star in your own life. The funny thing is that you don't really care. You are so pleased that people want to spend time with your child that you are OK moving behind the scenes. Your baby is the star, and her mom is the director. You are somewhere between the "grip" and the "best boy." Do you know what they are? Of course not. No one does. But they still make the credits. That is you. And you know what the funny thing is? It's enough - more than enough, actually. You actually managed to check your ego at the door. Not a bad first step for a man.
Let me throw one more analogy at you before I go: Military personnel are proud of reminding civilians that they do more before 6 a.m. than most people do all day.
Heck, they must all be parents.
Want to see more?
Craig Shoemaker: Conquering Fatherhood With Laughter
How I Knew I Was a Dad: 15 Surefire Ways
Last edited by Cat Dancer; September 18th, 2008 at 11:45 AM. Reason: fixed odd characters
May 18th, 2004, 02:30 PM #2Full Member
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Dads Facing the Dawn of a New Era
David this article extraordinary ...and should be read by every new father...a child is the most amazing thing that happens in an individual's life....but it is difficult to know what to expect. This should somehow be placed in a gift basket to dad when he has a child. We wouldn't be able to survive parenting without a great deal of humor!
May 18th, 2004, 11:40 PM #3
Dads Facing the Dawn of a New EraOriginally Posted by Janeanne
We wouldn't be able to survive parenting without a great deal of humor!
May 19th, 2004, 01:40 AM #4Full Member
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Dads Facing the Dawn of a New Era
After David's clear instructions on entering quotes...let's give it a try!
David wrote:
especially not the terrible teens! :o)
May 19th, 2004, 01:45 AM #5
Dads Facing the Dawn of a New Era
There you go! well done :o)
Now, to get a little fancier, instead of
[b]David wrote:[/b] [quote]especially not the terrible teens! :o)[/quote]
[quote="David"]especially not the terrible teens! :o)[/quote]
Originally Posted by David
May 19th, 2004, 07:07 PM #6Full Member
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Dads Facing the Dawn of a New EraOriginally Posted by David