Nanocomposite films and coatings produced by interaction between graphite oxide and Congo red

Nanocomposite films and coatings were produced from the aqueous solutions containing different proportions of graphite oxide (GO) and Congo red by filtering through a polycarbonate membrane filter into alkaline media. They were examined by electron microscopy, Raman and FTIR spectroscopy, XRD, contact angle, and electrical conductivity measurements. It was established that the Congo red is able to interact through its amino groups with different functional groups of GO to form larger moieties composed of the nanoplatelets of GO. Raman spectroscopy revealed quinoid-like ring structure for dye adhering to the GO. In the case when the interaction occurs with the terminal functional groups located on the edges of the nanoplateletes of GO, larger crystallites in the nanocomposite are formed. The interaction between the Congo red and functional groups of GO situated in a basal plane leads to more compact structure of the nanocomposite. Pulsed laser treatment was used to reduce GO to graphene. Raman spectra of laser treated areas show positive effect of addition of the Congo red on the graphene yield in nanocomposite coatings after the laser treatment.     

Unraveling the Interaction between the LPS O‐Antigen of Burkholderia anthina and the 5D8 Monoclonal Antibody by Using a Multidisciplinary Chemical Approach,with Synthesis,NMR, and Molecular Modeling Methods

The interaction between the O‐chain from the lipopolysaccharide from Burkholderia anthina and a lipopolysaccharide‐specific monoclonal antibody (5D8) has been studied at high resolution by NMR spectroscopy. In particular, the 5D8‐bound epitope of the saccharide entity has been unraveled by a combination of saturation transfer difference (STD) and transferred NOESY (tr‐NOESY) experiments performed on the 5D8/polysaccharide complex. To dissect the fine details of the molecular recognition events, further experiments with simpler carbohydrate ligands were carried out. Thus, experiments were also performed with ad hoc synthesized trisaccharide and hexasaccharide O‐antigen repeating units. By using this multidisciplinary approach (chemical synthesis, NMR spectroscopy and molecular dynamics simulation), determination of the binding epitope and the contribution to the binding of the sugar units composing the O‐chain have been determined.     

Carbon emission offsets for aviation-generated emissions due to international travel to and from New Zealand

International air transport emissions are not subject to liability under the Kyoto Protocol. However, pressure is mounting globally for international aviation to be included in post-Kyoto arrangements. In the absence of international collective action, a number of so-called carbon offsetting schemes have emerged that allow individual travellers and companies to compensate for their international air travel emissions. These schemes offer technological solutions, such as planting sink forests to sequester emissions. To consider the implications of future collective action, this paper presents a case study assessment of the physical feasibility of five schemes for all short duration journeys to and from New Zealand. This is the first comprehensive national-level case study assessment of competing offsetting options for international aviation emissions in the peer-reviewed literature. The CO₂-e emissions produced by the air travel of international visitors to New Zealand, and for New Zealand residents travelling overseas, is calculated in this paper to be 7893 and 3948 Gg, respectively, in 2005. It is then shown that no single offsetting scheme targeted inside the country appears physically and/or politically realistic. This indicates the sheer size of these emissions, and the challenge that the international community faces for collective action on this matter.     

消费和工业应用中的低功耗考量

消费和工业市场要求在新产品设计中提高能源效率.便携产品需要新一代技术来延长电池使用寿命,而大型产品(如白色家电)则需要提高能源效率来保持竞争优势.很多情况下,利用电子组件替换机械组件可以降低板卡功耗,附加的软件控制能够精确调整应用的功率性能.     

Performance evaluation of emergency department physicians using robust value-based additive efficiency model

We propose a novel variant of the value-based additive data envelopment analysis model. It conducts a comprehensive robustness analysis of efficiency outcomes for all feasible input and output weights using mathematical programming and the Monte Carlo simulation. We also introduce the original procedures for selecting a common vector of weights and an approach for investigating the stability of results in a multiscenario setting. The presented framework is applied to evaluate the performance of emergency department physicians using data from the Children's Hospital of Eastern Ontario in Ottawa. Our focus is on the physicians' performance when dealing with groups of patients' complaints related to abdominal pain and constipation, fever, extremity injury, head injury, and laceration/puncture. The obtained results emphasize the strong dependence of the physicians' performances on the selected weight vectors. However, they prove helpful in pointing out overall good performers who can serve as universal benchmarks or niche performers being markedly better in providing care to a given complaint group. They also offer a basis for developing an improvement plan for the underperforming physicians, identifying the priorities for a practice-oriented model, and recognizing the most challenging patients' complaints.     

Interaction between graphite oxide and Congo red in aqueous media

Interaction between graphite oxide and Congo red, a diazo dye containing NH₂ and SO₃ functional groups, was studied using UV–vis, FTIR, capillary electrophoresis and potentiometric methods. UV–vis experiments managed to elicit a colorful set of reactions, which were dependent on the sonication of solution. It was established that the molecules of Congo red after sonication are able to penetrate through the hydration shell and extract the protons attached to the functional groups on the surface of graphite oxide. Interaction between the graphite oxide particles and Congo red molecules is suggested to stabilize the aqueous suspensions of single-layer graphite oxide sheets. Potentiometric titration data show that the Congo red molecules adsorbed on the surface of graphite oxide are able to prevent the penetration of OH⁻ ions to reach the acidic functional groups inside the graphite oxide stacks. Electrostatic repulsion among these functional groups is quite high. Ionization of the graphite oxide colloidal particles with adsorbed Congo red molecules leads to the significant changes in their conformation.     

Geographical Origin Identification of Moldavian Wines by Neutron Activation Analysis

To get more data regarding the elemental transfer from soil to wine, the neutron activation analysis was used to determine 35 elements in vineyard chernozem soil and 18 elements in wines from Romanesti and Cricova, Republic of Moldova. Soil elemental content allowed evidencing more similarities between considered soils and the Upper Continental Crust and the World Average Soil as well as to calculate the soil-to-wine transfer factor for 18 of investigated elements. From all 28 trace elements evidenced in soil, only 13, the soluble ones, were found in all wine samples, which finally allowed determining the corresponding transfer factors whose values varied between 0.02 mg/l (U) and 38 mg/l (K). In this regard, all sorts of wines showed a significant concentration of potassium, varying from 370 to 700 mg/l. A subsequent discriminant analysis allowed discriminating all wine samples according to their types: red and white as well as their origin.     

Hydrophilic monolith with ethylene glycol-based grafts prepared via surface confined thiol-ene click photoaddition

Macroporous polymeric monolith bearing thiol-reactive surface functionalities was prepared within micrometer-sized fused silica capillary column by photochemically-driven free radical copolymerization of N-acryloxysuccininimide and ethylene dimethacrylate in the presence of toluene as porogenic solvent, hereafter poly(NAS-co-EDMA), and subsequent surface grafting of allylamine through nucleophilic substitution reaction. The pore surface with pendant allyl moieties was further functionalized via a two-step thiol-ene click reaction with thiol-containing oligo(ethylene glycol) and mercaptoethanol, successively. The surface hydration ability, i.e. hydrophilic character, of the as-obtained monolith was evaluated as a function of the water-content of the liquid fluid environment through electrochromatographic evaluation of the retention properties of the -(O-CH₂-CH₂)-like surface-functionalized capillary monolith. A major result was that the so called hydrophilic interaction electrochromatographic mode was observed at a given mobile phase composition. An example is given for the separation of phenol-derivatives, with the most hydrophilic one being the most retained. In addition, the hydrophilic interaction based separation allowed for reduced analysis time as compared to the separation observed under reversed-phase separation mode using analogous monolithic stationary phase. Finally, the versatility of the thiol-ene photoaddition approach is demonstrated with an example of C18-like monolith for reversed-phase separation application.     

Micro- and Nanostructural Characteristics of Particles Before and After an Exhaust Gas Recirculation System Scrubber

This work provides insight into the morphology and mixing state of submicron particles in diesel exhaust from a ship engine with an exhaust gas recirculation scrubber. Particles from this low-speed ship engine on test bed were collected using a microinertial impactor with transmission electron microscopy (TEM) grids on two stages. Micro- and nanostructural characteristics of single particles were studied by TEM. Image analysis was carried out on overview and high-resolution images, revealing influence of the exhaust gas treatment (scrubber) on the particle morphology and mixing state. Soot agglomerates were found to be collapsed after scrubber, reflected by their change in fractal dimension (D_f ) from 1.88 to 2.13. Soot was predominantly found internally mixed with other components, with a higher degree of internal mixing observed after scrubber. Soot nanostructural characteristics on the near atomic scale such as layer distance, lamella length, and tortuosity were not observed to be influenced by the scrubber. We also found that particles in the size range between 30 and 50 nm, which were abundant in the exhaust before and after scrubber, were not graphitic soot. Furthermore, we found indications that these particles are composed of other crystalline material (salts).

Copyright 2013 American Association for Aerosol Research