Imagined and occasional co-presence in open adoption: how adoptive parents mediate birth connections.

This chapter explores the ways that adopted children and their birth parents can remain co-present following adoption. It focuses specifically on public adoption of children who have been in the care of child welfare services, and draws on adoptive parents’ accounts of their experiences of adoption openness. The distinctive features of co-presence between children and their birth parents after adoption are: that it is mediated by negotiated contact agreements and through on-going adoptive family practices; and that it is occasional, with its infrequency displaying the status and significance of birth relationships. Physical co-presence can in some cases be achieved through face-to-face contact meetings, however, even when this not possible, birth parents can be present in the hearts and minds of the adoptive family, constituting a form of imagined co-presence. The chapter explores how adopters achieve, delimit and mediate imagined and physical co-presence between their child and birth parent and concludes by considering the emergence of virtual co-presence via online social media.

Simultaneous remote haptic collaboration for assembling tasks

Stand-alone virtual environments (VEs) using haptic devices have proved useful for assembly/disassembly simulation of mechanical components. Nowadays, collaborative haptic virtual environments (CHVEs) are also emerging. A new peer-to-peer collaborative haptic assembly simulator (CHAS) has been developed whereby two users can simultaneously carry out assembly tasks using haptic devices. Two major challenges have been addressed: virtual scene synchronization (consistency) and the provision of a reliable and effective haptic feedback. A consistency-maintenance scheme has been designed to solve the challenge of achieving consistency. Results show that consistency is guaranteed. Furthermore, a force-smoothing algorithm has been developed which is shown to improve the quality of force feedback under adverse network conditions. A range of laboratory experiments and several real trials between Labein (Spain) and Queen’s University Belfast (Northern Ireland) have verified that CHAS can provide an adequate haptic interaction when both users perform remote assemblies (assembly of one user’s object with an object grasped by the other user). Moreover, when collisions between grasped objects occur (dependent collisions), the haptic feedback usually provides satisfactory haptic perception. Based on a qualitative study, it is shown that the haptic feedback obtained during remote assemblies with dependent collisions can continue to improve the sense of co-presence between users with regard to only visual feedback.

The effect of co-precipitation on cadmium(II) adsorption on hydrous aluminium(III) hydroxide in the presence of a range of chelates

The adsorption of cadmium(II) on freshly precipitated aluminium(III) hydroxide in the presence of a range of chelates has been investigated. By precipitating the metal, chelate and adsorbent together it is possible to change the pH variation of the metal-complex adsorption from anionic, ligand-like, binding to cationic binding. This is a general phenomenon and is explained by the formation of a ternary Al-O-Cd-L surface species. As a consequence of the preparation method, the pH edge is found to shift to lower pH values in the presence of the chelate which gives rise to an apparent increase in adsorption of Cd2+. This increase is, in general, most pronounced at [chelate] / [metal] > 1. Computer modelling shows that the observed trends result from the competition between Al-O-Cd-L and Al-L for the available aluminium( III) binding sites. The enhanced adsorption in the presence of phenylenediaminetetraacetate is anomalous since it is observed at a [ chelate] / [metal] approximate to 0.1 and cannot be interpreted by the simple competition model.

Influence of plasticizer type and storage conditions on properties of poly(methyl vinyl ether-co-maleic anhydride) bioadhesive films

Poly(methyl vinyl ether-co-maleic anhydride) formed films from aqueous formulations with characteristics that are ideal as a basis for producing a drug-containing bioadhesive delivery system when plasticized with a monohydroxyl functionalized plasticizer. Hence, films containing a novel plasticizer, tripropylene glycol methyl ether (TPME), maintained their adhesive strength and tensile properties when packaged in aluminized foil for extended periods of time. Films plasticized with commonly used polyhydric alcohols, such as the glycerol in this study, underwent an esterification reaction that led to polymer crosslinking, as shown in NMR studies. These revealed the presence of peaks in the ester/carbonyl region, suggesting that glyceride residue formation had been initiated. Given the polyfunctional nature of glycerol, progressive esterification would result in a polyester network and an accompanying profound alteration in the physical characteristics. Indeed, films became brittle over time with a loss of both the aqueous solubility and bioadhesion to porcine skin. In addition, a swelling index was measurable after 7 days, a property not seen with those films containing TPME. This change in bioadhesive strength and pliability was independent of the packaging conditions, rendering the films that contain glycerol as unsuitable as a basis for topical bioadhesive delivery of drug substances. Consequently, films containing TPME have potential as an alternative formulation strategy.

Modulating the selectivity for CO and butane oxidation over heterogeneous catalysis through amorphous catalyst coatings

The preparation of porous films directly deposited onto the surface of catalyst particles is attracting increasing attention. We report here for the first time a method that can be carried out at ambient pressure for the preparation of porous films deposited over 3 mm diameter catalyst particles of silica-supported Pt-Fe. Characterization of the sample prepared at ambient pressure (i.e., open air, OA) and its main structural differences as compared with a Na-A (LTA) coated catalyst made using an autoclave-based method are presented. The OA-coated material predominantly exhibited an amorphous film over the catalyst surface with between 4 and 13% of crystallinity as compared with fully crystallized LTA zeolite crystals. This coated sample was highly selective for CO oxidation in the presence of butane with no butane oxidation observed up to 350 degrees C. This indicates, for the first time, that the presence of a crystalline membrane is not necessary for the difference in light off temperature between CO and butane to be achieved and that amorphous films may also produce this effect. An examination of the space velocity dependence and adsorption of Na+ on the catalysts indicates that the variation in CO and butane oxidation activity is not caused by site blocking predominantly, although the Pt activity was lowered by contact with this alkali.

Identifying an O-2 supply pathway in CO oxidation on Au/TiO2(110): A density functional theory study on the intrinsic role of water

Au catalysis has been one of the hottest topics in chemistry in the last 10 years or so. How O-2 is supplied and what role water plays in CO oxidation are the two challenging issues in the field at the moment. In this study, using density functional theory we show that these two issues are in fact related to each other. The following observations are revealed: (i) water that can dissociate readily into OH groups can facilitate O-2 adsorption on TiO2; (ii) the effect of OH group on the O-2 adsorption is surprisingly long-ranged; and (iii) O-2 can also diffuse along the channel of Ti (5c) atoms on TiO2(1 10), and this may well be the rate-limiting step for the CO oxidation. We provide direct evidence that O-2 is supplied by O-2 adsorption on TiO2 in the presence of OH and can diffuse to the interface of Au/TiO2 to participate in CO oxidation. Furthermore, the physical origin of the water effects on Au catalysis has been identified by electronic structure analyses: There is a charge transfer from TiO2 in the presence of OH to O-2, and the O-2 adsorption energy depends linearly on the 02 charge. These results are of importance to understand water effects in general in heterogeneous catalysis.

The catalytic role of water in CO oxidation

Water, one of the most popular species in our planet, can play a catalytic role in many reactions, including reactions in heterogeneous catalysis. In a recent experimental work, Bergeld, Kasemo, and Chakarov demonstrated that water is able to promote CO oxidation under low temperatures (similar to200 K). In this study, we choose CO oxidation on Pt(111) in the presence of water as a model system to address the catalytic role of water for surface reactions in general using density functional theory. Many elementary steps possibly involved in the CO oxidation on Pt(111) at low temperatures have been investigated. We find the following. First, in the presence of water, the CO oxidation barrier is reduced to 0.33 eV (without water the barrier is 0.80 eV). This barrier reduction is mainly due to the H-bonding between the H in the H2O and the O at the transition state (TS), which stabilizes the TS. Second, CO can readily react with OH with a barrier of 0.44 eV, while COOH dissociation to produce CO2 is not easy (the barrier is 1.02 eV). Third, in the H2O+OH mixed phase, CO can be easily converted into CO2. It occurs through two steps: CO reacts with OH, forming COOH; and COOH transfers the H to a nearby H2O and, at the same time, an H in the H2O transfers to a OH, leading to CO2 formation. The reaction barrier of this process is 0.60 eV under CO coverage of 1/6 ML and 0.33 eV under CO coverage of 1/3 ML. The mechanism of CO oxidation at low temperatures is discussed. On the basis of our calculations, we propose that the water promotion effect can in general be divided into two classes: (i) By H-bonding between the H of H2O and an electron negative species such as the O in the reaction of CO+O+H2O-->CO2+H2O, H2O can stabilize the TS of the reaction and hence reduce the barrier. (ii) H2O first dissociates into H and OH and then OH or H participates directly in the reaction to induce new reaction mechanism with more favorable routes, in which OH or H can act as an intermediate. (C) 2003 American Institute of Physics.

The effects of the specific adsorption of anion on the reactivity of the Ru(0001) surface towards CO adsorption and oxidation: in situ FTIRS studies

The dynamics of adsorption and oxidation of CO on Ru(0001) electrode in sulfuric acid solution have been studied using in situ FTIR spectroscopy under potential control and at open circuit, the latter at 20 and 55 degrees C. The in situ IR data show clearly that the bisulfate anion adsorbs on the Ru(0001) surface over the potential range from -200 mV to 350 mV (vs. Ag/AgCl) at 20 degrees C in the absence and presence of adsorbed CO; however, increasing the temperature to 55 degrees C and/ or increasing the concentration of dissolved O-2 reduces the bisulfate adsorption. The formation of surface (hydro-) oxide at higher potentials replaces the bisulfate adsorbates. Both linear (COL) and three-fold hollow bonded CO (COH) adsorbates were produced following CO adsorption at Ru(0001) in H2SO4, as was observed in our previous studies in HClO4. However, the amount of adsorbed CO observed in H2SO4 was ca. 10% less than that in HClO4; in addition, the COL and COH frequencies were higher in H2SO4, and the onset potential for COads oxidation 25 mV lower. These new results are interpreted in terms of a model in which the adsorbed bisulfate weakens the CO adlayer, allowing the active Ru oxide layer to form at lower potentials. Significantly different results were observed at open circuit in H2SO4 compared both to the data under potential control and to our earlier data in HClO4, and these observations were rationalized in terms of the adsorbed HSO4- anions (pre-adsorbed at -200 mV) inhibiting the oxidation of the surface at open circuit (after stepping from the initial potential of -200 mV), as the latter was no longer driven by the imposed electrochemical potential but via chemical oxidation by trace dissolved O-2. Results from experiments at open circuit at 55 degrees C and using oxygen-saturated H2SO4 supported this model. The difference in Ru surface chemistry between imposed electrochemical control and chemical control has potential implications with respect to fuel cell electrocatalysis.

TAP studies of CO oxidation over CuMnOX and Au/CuMnOX catalysts

The mechanism of CO oxidation reactions over undoped and gold-doped CuMnOX (Hopcalite) catalysts has been examined using a temporal analysis of products (TAP) reactor Gold doping has been found to increase the activity of the mixed oxide catalyst significantly however using consecutive pulsing TAP experiments the presence of gold was not found to affect the contribution of the Langmuir-Hinshelwood mechanism Conversely gold doping was found to promote the Mars van Krevelen mechanism Using CO and O-2 multi-pulse TAP experiments the gold was found to modify the catalyst surface such that it stores much more oxygen that is active for the CO oxidation The CO multi-pulse experiments indicated that two distinct types of active oxygen species were found to be involved in the CO oxidation One type was observed in a similar amount on both doped and undoped catalysts and was associated with mixed oxide while the second type was only found on the gold-doped catalyst and was therefore clearly associated with the presence of gold on the catalyst surface The latter was found to be much less active than the oxygen inherent to the oxide but was at a concentration of approximately 10 times larger leading to the enhanced activity observed on gold doping (C) 2010 Elsevier Inc All rights reserved

Origin of Low CO2 Selectivity on Platinum in the Direct Ethanol Fuel Cell

Calculated answer: First-principles calculations have been applied to calculate the energy barrier for the key step in CO formation on a Pt surface (see picture; Pt blue, Pt atoms on step edge yellow) to understand the low CO2 selectivity in the direct ethanol fuel cell. The presence of surface oxidant species such as O (brown bar) and OH (red bar) led to an increase of the energy barrier and thus an inhibition of the key step. © 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Enhancement of triclabendazole action in vivo against a triclabendazole-resistant isolate of Fasciola hepatica by co-treatment with ketoconazole

An in vivo study in the laboratory rat model was carried out to monitor morphological changes in adult Fasciola hepatica over a 4-day period resulting from combination treatment of triclabendazole (TCBZ) and the metabolic inhibitor, ketoconazole (KTZ). Rats were infected with the TCBZ-resistant Oberon isolate of F. hepatica and divided into 3 groups at 12 weeks post-infection. The first group was dosed orally with TCBZ at a dosage of 10 mg/kg and KTZ at a dosage of 10 mg/kg. Flukes were recovered at 24, 48, 72 and 96h post-treatment (p.t.). A second group of rats was treated with TCBZ alone (10 mg/kg) and sacrificed at 96 h p.t. The third group acted as untreated controls. Surface changes were monitored by scanning electron microscopy (SEM). In flukes from the TCBZ+ KTZ-treated group, the results showed a progressive and time-dependent increase in the level of disruption to the tegumental syncytium. Swelling, furrowing, blebbing and sloughing of the syncytium increased with time p.t. Another feature seen was a thick layer of tegumental shedding in some fluke samples at different times p.t. By comparison, flukes treated with TCBZ alone remained unaffected. The results demonstrated that the Oberon isolate is only sensitive to drug action in the presence of ketoconazole, indicating that combining triclabendazole with a metabolic inhibitor could be used to preserve the effectiveness of the drug against TCBZ-resistant populations of F. hepatica. (C) 2010 Elsevier B.V. All rights reserved.

Potentiation of triclabendazole action in vivo against a triclabendazole-resistant isolate of Fasciola hepatica following its co-administration with the metabolic inhibitor, ketoconazole

An in vivo study in the laboratory rat model has been carried out to monitor morphological changes in adult Fasciola hepatica over a 4-day period resulting from co-treatment with triclabendazole (TCBZ) and ketoconazole (KTZ), a cytochrome P450 inhibitor. Rats were infected with the triclabendazole-resistant Oberon isolate of F. hepatica, dosed orally with triclabendazole at a dosage of 10mg/kg live weight and ketoconazole at a dosage of 10mg/kg live weight. Flukes were recovered at 24, 48, 72 and 96 h post-treatment (p.t.) and changes to fluke ultrastructure were assessed using transmission electron microscopy (TEM). Results showed an increase in the severity of changes to the fluke ultrastructure with time p.t. Swelling of the basal infolds and the associated mucopolysaccharide masses became more severe with time. Golgi complexes, if present, were greatly reduced in size and number by 96 h p.t., and sub-tegumental flooding was seen from the 72 h time-period onwards. Some sloughing of the tegumental covering over the spines was observed at 96 h p.t. The results demonstrated that the Oberon isolate is more sensitive to TCBZ action in the presence of KTZ than to TCBZ alone, reinforcing the idea that altered drug metabolism is involved in the resistance mechanism. Moreover, they support the concept that TCBZ+inhibitor combinations (aimed at altering drug pharmacokinetics and potentiating the action of TCBZ) could be used in the treatment of TCBZ-R populations of F. hepatica.

Guest sorption and desorption in the metal-organic framework [Co(INA)(2)] (INA = isonicotinate) - evidence of intermediate phases during desorption

The metal-organic framework [Co(INA)(2)].0.5EtOH (INA = isonicotinate, NC5H4-4-CO2-), 1 was synthesised under solvothermal conditions. Its X-ray crystal structure shows channels containing ethanol guests which are hydrogen-bonded to carboxylate oxygens of the framework. The pyridyl rings of the framework alternate between `open' and `closed' positions along the channels resulting in large variation in the channel cross-sectional area from ca. 1.4 by 2.3 at the narrowest point to 4.9 by 5.3 at the widest. Despite the very small windows, the ethanol guests (of van der Waals diameter ca. 4.2-6.1 Angstrom) may be reversibly desorbed and sorbed into the structure quantitatively, as shown by in situ variable-temperture IR spectroscopy and XRPD. The single-crystal structure of the desolvated form [Co(INA)(2)]2 shows that there is no change in the overall connectivity on desolvation, but the rotational positions of the pyridine rings are altered. This suggests that pyridyl rotation may occur to allow guests to pass in and out. When the synthesis was conducted in 1-propanol solvent [Co(INA)(2)].0.5Pr(n)OH.H2O 3, was obtained, and a single-crystal X-ray structure revealed the same overall connectivity as in 1 but with pyridine rings disordered over closed and open positions. There was no evidence of included guests from X-ray crystallography, suggesting that they are also highly disordered. Variable-temperature XRPD performed on bulk samples showed peaks which were unsymmetrical and exhibited shoulders, suggesting that for each pattern obtained the material actually consisted of several closely-related phases. The movements of the peaks during desolvation showed the presence of intermediate phases before the final desolvated product was formed. The peak positions of the intermediate phases matched more closely with the calculated pattern for 3 than with 1 or 2, suggesting that they may have disordered structures similar to 3. The results also suggest that the intermediate phase represents an initial increase in volume before a larger decrease in volume occurs to give the final desolvated material.