Study of electrocatalysts for oxygen reduction based on electroconducting polymer and nickel

The properties and electrocatalytic activity were studied of composite carbon‐supported materials based on heterocyclic polymer and nickel, in particular carbon/polyaniline/nickel, carbon/polypyrrole/nickel, carbon/poly(3‐methylthiophene)/nickel, as well as their precursors, carbon/polyaniline, carbon/polypyrrole, and carbon/poly(3‐methylthiophene). The materials were characterized by means of thermogravimetric analysis (TGA), scanning electron microscopy (SEM), EDAX, and electrochemical methods, such as cyclic voltammetry and linear voltammetry using RDE. SEM show porous materials, with a particle size of around 0.3 μm. It was found that in nickel‐modified catalysts between 5 and 6 wt % of nickel is obtained. TGA and FTIR show that the modification with nickel alters the polymer bonds. Curves from cyclic voltammetry show cathodic peaks corresponding to the oxygen reduction reaction (ORR) in all materials, occurring at relatively low potentials. Based on the potential range for ORR as well as kinetic parameters obtained from linear voltammetry using RDE, it was concluded that C‐Ppy‐Ni shows the best performance for ORR in acidic medium. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Characterization of composite materials of electroconductive polymer and cobalt as electrocatalysts for the oxygen reduction reaction

Platinum-free electrocatalysts based on electroconductive polymer, modified with cobalt, were prepared and characterized for the oxygen reduction reaction (ORR). The carbon-supported materials were: carbon/polyaniline/cobalt, carbon/polypyrrole/cobalt and carbon/poly(3-methylthiophene)/cobalt. Also the corresponding cobalt-free precursors were studied. EDAX studies show that in cobalt-modified catalysts, significant percentages of cobalt, between 5 and 7% in weight, are present. FTIR, TGA, and EDAX studies confirmed that the addition of cobalt modifies the chemical structure of C–Pani, C–Ppy, and C–P3MT materials. Cyclic voltammetry shows reduction peaks corresponding to the ORR for all materials and kinetic parameters were calculated based on lineal voltammetry using RDE at different rotating speeds. It was found that C–P3MT–Co has highest exchange current densities, followed by C–Ppy and C–Ppy–Co. All samples have Tafel slopes between −110 and −120 V/dec, indicating that the first electron transfer is the decisive step in the global ORR. Potentiostatic tests showed an adequate stability of cobalt-modified samples in acid medium at ORR potentials. Based on the potential range at which ORR occurs, the exchange current density and stability tests, it is concluded that the best material for potential application as fuel cell cathode catalyst is C–Ppy–Co.     

Randomized controlled trial of physician-directed versus respiratory therapy consult service-directed respiratory care to adult non-ICU inpatients

Although current evidence suggests that respiratory care protocols can enhance allocation of respiratory care services while conserving costs, a randomized trial is needed to address shortcomings of available studies. We therefore conducted a randomized controlled trial comparing respiratory care for adult non-ICU inpatients directed by a Respiratory Therapy Consult Service (RTCS) versus respiratory care by managing physicians. Eligible subjects were adult non-ICU inpatients whose physicians had prescribed specific respiratory care services. Consecutive eligible patients were approached for consent, after which a blocked randomization strategy was used to assign patients to (1) Physician-directed respiratory care, in which the prescribed physician respiratory care orders were maintained (n = 74), or (2) RTCS-directed respiratory care, in which the physician's respiratory care orders were preempted by a respiratory care plan generated by the RTCS (n = 71). Specifically, these patients were evaluated by an RTCS therapist evaluator whose respiratory care plan was based on sign/symptom-based algorithms drafted to comply with the American Association for Respiratory Care (AARC) Clinical Practice Guidelines. Appropriateness of respiratory care orders was assessed as agreement between the prescribed respiratory care plan and an algorithm-based "standard care plan" generated by an expert therapist who was blind to the patient's actual orders. The compared groups were similar at baseline regarding demographic features, admission diagnostic category, smoking status, and Triage Score (mean, 3.8 +/- 0.9 SD [RTCS] versus 3.7 +/- 1.0). Similarly, no differences were observed between RTCS-directed and physician-directed respiratory care regarding hospital mortality rate (5.7 versus 5.6%), hospital length of stay (7.9 +/- 9.0 versus 7.7 +/- 7.3 d), total number of respiratory care treatments delivered (30.3 +/- 30 versus 31.6 +/- 30.5), or days requiring respiratory care (4.2 +/- 5.2 versus 4.1 +/- 3.6). Notably, using both a stringent (S) and a liberal (L) criterion for agreement, RTCS-directed respiratory care demonstrated better agreement with the "standard care plan" (82 +/- 17% [S] and 86 +/- 16% [L]) than did physician-directed respiratory care (64 +/- 21% [S] and 72 +/- 23% [L]) (p < 0.001). Finally, the true cost of respiratory care treatments was slightly lower with RTCS-directed respiratory care (mean, $235.70 versus $255.70/pt, p = 0.61). We conclude that (1) compared with physician-directed respiratory care, the RTCS prescribed a similar number and duration of respiratory care services at a slight savings (that did not achieve statistical significance) and without any increased adverse events; and (2) compared with physician-directed respiratory care, RTCS-directed respiratory care showed greater agreement with Clinical Practice Guideline-based algorithms.     

The influence of emotion regulation on social interactive decision-making.

Although adequate emotion regulation is considered to be essential in every day life, it is especially important in social interactions. However, the question as to what extent two different regulation strategies are effective in changing decision-making in a consequential socially interactive context remains unanswered. We investigated the effect of expressive suppression and emotional reappraisal on strategic decision-making in a social interactive task, that is, the Ultimatum Game. As hypothesized, participants in the emotional reappraisal condition accepted unfair offers more often than participants in the suppression and no-regulation condition. Additionally, the effect of emotional reappraisal influenced the amount of money participants proposed during a second interaction with partners that had treated them unfairly in a previous interaction. These results support and extend previous findings that emotional reappraisal as compared to expressive suppression, is a powerful regulation strategy that influences and changes how we interact with others even in the face of inequity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

“Technically Unavoidable” in Terms of Genetically Modified Organisms – an Approach for Food Control

In case of findings of authorized genetically modified (gm) plant ingredients below the 0.9 per cent threshold, exceptions from labelling requirements according to regulation (EC) No. 1829/2003 can only be made, “provided that this presence is adventitious or technically unavoidable”. The authors describe factors that should be considered regarding contaminations by gm plant ingredients as technically unavoidable or not. A practical approach for interpretation, taking into account quality control measures and documentation as well as present findings in comparable products is proposed. Received: February 23, 2007     

高速公路汽车辅助驾驶安全换道模型

为解决高速公路行车危险状态下驾驶员有意识换道过程中发生的车辆碰撞等交通事故问题,在前期研究车道偏离预警的基础上.针对确立的典型换道场景,建立了更加符合实际的基于换道过程中车辆加速行为的安全换道模型,并借助Matlab软件开发的仿真程序对建立的模型进行了仿真分析。结果表明,本文建立的模型具有较好的实用性,可为进一步建立车辆安全换道辅助系统奠定基础。     

Expanding the representation of user activities

Space is often designed based on the representations of user activities (i.e. lists, organograms or flowcharts) that streamline user activities in stepwise, oversimplified, representations that may leave insufficient room for future activity development. However, design can anticipate activity development if users are able to represent their own activities while participating in the design process. A case study of a medical imaging centre reveals that once users have such opportunity, their spatial practices are not only taken into account but also expanded. The designers, the users and the researchers created a range of instruments to expand across three units of analysis: operations, actions and activities. As a result, the representations of space proffered by the designers were expanded to a space of representation for the users, where new ways of working were realized. Based on this study, an integrated model for the production of space and the development of activity is proposed.     

The tip of the hydrophobic hairpin of colicin U is dispensable for colicin U activity but is important for interaction with the immunity protein

The hydrophobic C terminus of pore-forming colicins associates with and inserts into the cytoplasmic membrane and is the target of the respective immunity protein. The hydrophobic region of colicin U of Shigella boydii was mutated to identify determinants responsible for recognition of colicin U by the colicin U immunity protein. Deletion of the tip of the hydrophobic hairpin of colicin U resulted in a fully active colicin that was no longer inactivated by the colicin U immunity protein. Replacement of eight amino acids at the tip of the colicin U hairpin by the corresponding amino acids of the related colicin B resulted in colicin U(575-582ColB), which was inactivated by the colicin U immunity protein to 10% of the level of inactivation of the wild-type colicin U. The colicin B immunity protein inactivated colicin U(575-582ColB) to the same degree. These results indicate that the tip of the hydrophobic hairpin of colicin U and of colicin B mainly determines the interaction with the corresponding immunity proteins and is not required for colicin activity. Comparison of these results with published data suggests that interhelical loops and not membrane helices of pore-forming colicins mainly interact with the cognate immunity proteins and that the loops are located in different regions of the A-type and E1-type colicins. The colicin U immunity protein forms four transmembrane segments in the cytoplasmic membrane, and the N and C termini face the cytoplasm.     

Gebäudehülle aus Stahl und Glas – Das neue Citroën‐Ausstellungszentrum in Paris

The steel and glass façade – the new Citroën‐Show room in Paris. Since 1927 the address of the first exhibition centre of the Citroën Company is 42, Avenue des Champs‐Elysées, Paris. After the decision of the complete removal of the old building now at the same place a new and extravagant structure is being built. Roof and façade of the new structure form a single unit, beginning from the bottom of the front over the roof towards the bottom of the rear façade. Numerous small translucent pyramids brought in place on the surface of the façade provide a sculptural impression. Illumination and brightness of the interior of the showroom is guaranteed. Besides the architectural challenges technical requirements had to be fulfilled. The paper deals with the technical and engineering aspects that yield from the design of steel and glass structure, building physics and execution.     

Colicin U, a novel colicin produced by Shigella boydii

A novel colicin, designated colicin U, was found in two Shigella boydii strains of serovars 1 and 8. Colicin U was active against bacterial strains of the genera Escherichia and Shigella. Plasmid pColU (7.3 kb) of the colicinogenic strain S. boydii M592 (serovar 8) was sequenced, and three colicin genes were identified. The colicin U activity gene, cua, encodes a protein of 619 amino acids (Mr, 66,289); the immunity gene, cui, encodes a protein of 174 amino acids (Mr, 20,688); and the lytic protein gene, cul, encodes a polypeptide of 45 amino acids (Mr, 4,672). Colicin U displays sequence similarities to various colicins. The N-terminal sequence of 130 amino acids has 54% identity to the N-terminal sequence of bacteriocin 28b produced by Serratia marcescens. Furthermore, the N-terminal 36 amino acids have striking sequence identity (83%) to colicin A. Although the C-terminal pore-forming sequence of colicin U shows the highest degree of identity (73%) to the pore-forming C-terminal sequence of colicin B, the immunity protein, which interacts with the same region, displays a higher degree of sequence similarity to the immunity protein of colicin A (45%) than to the immunity protein of colicin B (30.5%). Immunity specificity is probably conferred by a short sequence from residues 571 to residue 599 of colicin U; this sequence is not similar to that of colicin B. We showed that binding of colicin U to sensitive cells is mediated by the OmpA protein, the OmpF porin, and core lipopolysaccharide. Uptake of colicin U was dependent on the TolA, -B, -Q, and -R proteins. pColU is homologous to plasmid pSB41 (4.1 kb) except for the colicin genes on pColU. pSB41 and pColU coexist in S. boydii strains and can be cotransformed into Escherichia coli, and both plasmids are homologous to pColE1.