Electrochemical synthesis of polypyrrole layers doped with glutamic ions

Electrochemically synthesized polypyrrole thin films doped with glutamic ions were investigated as interesting materials for potential use as molecularly selective surfaces. Pyrrole and glutamate interact in aqueous solution, resulting in the formation of a prominent band at 240 nm in the absorption spectra of the solution. This feature was assigned to the formation of a complex, which significantly influences the electrochemical deposition of polypyrrole films doped with glutamate. It was also detected that oxidation of these complexes leads to the appearance of a shoulder in the absorption spectrum at 270 nm, which corresponds to the yellowish color of pyrrole aged under influence of air. A mechanism is proposed for polymer film growth in aqueous solutions containing monosodium L ‐glutamate and pyrrole. It takes into account the observed influence of the pH of the solution, the concentration of reagents, the zwitterionic properties of glutamate on deposition, and results from spectroscopic measurements. It is also shown that glutamic ions can electrochemically be released from the synthesized polymer layers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Fatigue strength of welded joints in austenitic Cr-Ni steels

Abstract

High quality corrosion resistant Cr-Ni steels are used in many branches of industry. Constructors are faced with the problem of correctly dimensioning statically and dynamically loaded parts, but have little data available for dynamically loaded welded constructions of high alloy austenitic steels. To close this gap fatigue strength tests were carried out on three different steels and five different welded joints.     

Use of an immunoassay as a means to detect polychlorinated biphenyls in animal fat

In this paper we describe the validation and utilization of the Hybrizyme TM DELFIA immunoassay for detecting polychlorinated biphenyls (PCBs) in animal fat. The immunoassay incorporates a rapid sample processing protocol that has been optimized to detect concentrations of PCBs in animal fat at or above 200ng/g. The limit of detection of the assay was less than 50ng/g. When the action level for the DELFIA assay was set at 100ng/g to detect samples having 200ng/g or more PCBs, the false negative rate was estimated at 0.2% . The false positive rate depends on the concentration of PCBs in the sample population and was estimated at 4% and 7% for samples having 10ng/ g and 20ng/g PCBs, respectively. By utilizing the DELFIA assay system to select for positive samples and GC/MS analysis for confirmation analysis, an accurate and cost-effective programme has been established for the high throughput detection of PCBs in animal products.     

Introduction to the Asian Energy Security project: Project organization and methodologies

The spectacular recent economic growth in the Asia-Pacific region in general, and in many of the economies of Northeast Asia in particular, has spurred a vast expansion in the need for energy services, and an expansion in the demand for the fuels that help to supply these services. Future projections suggest that the growth of fossil fuel use in Northeast Asia, especially in China, will have major consequences for financial and fuel markets and pollution both regionally and globally. Before the project described in this paper was initiated, there was no ongoing forum for energy experts from all of the countries of the region to meet, informally and in an unofficial capacity, to discuss openly and in a targeted fashion the energy situations in their countries, and to work together to evaluate the energy efficiency costs and benefits of different ways of meeting regional demand. The Asian Energy Security (AES) project provides such a forum, and as such constitutes a unique resource in the engagement of the countries of Northeast Asia on the topic of energy security.     

Oxidation of antibacterial molecules by aqueous ozone: moiety-specific reaction kinetics and application to ozone-based wastewater treatment

Ozone and hydroxyl radical (*OH) reaction kinetics were measured for 14 antibacterial compounds from nine structural families, to determine whether municipal wastewater ozonation is likely to result in selective oxidation of these compounds' biochemically essential moieties. Each substrate is oxidized by ozone with an apparent second-order rate constant, k'(O3,app) > 1 x 10(3) M(-1) s(-1), at pH 7, with the exception of N(4)-acetylsulfamethoxazole (K'(O3,app) is 2.5 x 102 M(-1) s(-1)). k'(O3,app) values (pH 7) for macrolides, sulfamethoxazole, trimethoprim, tetracycline, vancomycin, and amikacin appear to correspond directly to oxidation of biochemically essential moieties. Initial reactions of ozone with N(4)-acetylsulfamethoxazole, fluoroquinolones, lincomycin, and beta-lactams do not lead to appreciable oxidation of biochemically essential moieties. However, ozone oxidizes these moieties within fluoroquinolones and lincomycin via slower reactions. Measured k'(O3,app) values and second-order *OH rate constants, k'(*OH,app) were utilized to characterize pollutant losses during ozonation of secondary municipal wastewater effluent. These losses were dependent on k'(O3,app), but independent of k'(*OH,app). Ozone doses > or =3 mg/L yielded > or =99% depletion of fast-reacting substrates (K'(O3,app) > 5 x 10(4) M(-1) s(-1)) at pH 7.7. Ten substrates reacted predominantly with ozone; only four were oxidized predominantly by .OH. These results indicate that many antibacterial compounds will be oxidized in wastewater via moiety-specific reactions with ozone.     

Kinetics and mechanistic aspects of As(III) oxidation by aqueous chlorine, chloramines, and ozone: relevance to drinking water treatment

Kinetics and mechanisms of As(III) oxidation by free available chlorine (FAC-the sum of HOCl and OCl-), ozone (O3), and monochloramine (NH2Cl) were investigated in buffered reagent solutions. Each reaction was found to be first order in oxidant and in As(III), with 1:1 stoichiometry. FAC-As(III) and O3-As(III) reactions were extremely fast, with pH-dependent, apparent second-order rate constants, k'app, of 2.6 (+/- 0.1) x 10(5) M(-1) s(-1) and 1.5 (+/- 0.1) x 10(6) M(-1) s(-1) at pH 7, whereas the NH2Cl-As(III) reaction was relatively slow (k'app = 4.3 (+/- 1.7) x 10(-1) M(-1) s(-1) at pH 7). Experiments conducted in real water samples spiked with 50 microg/L As(III) (6.7 x 10(-7) M) showed that a 0.1 mg/L Cl2 (1.4 x 10-6 M) dose as FAC was sufficient to achieve depletion of As(III) to <1 microg/L As(III) within 10 s of oxidant addition to waters containing negligible NH3 concentrations and DOC concentrations <2 mg-C/L. Even in a water containing 1 mg-N/L (7.1 x 10(-5) M) as NH3, >75% As(III) oxidation could be achieved within 10 s of dosing 1-2 mg/L Cl2 (1.4-2.8 x 10(-5) M) as FAC. As(III) residuals remaining in NH3-containing waters 10 s after dosing FAC were slowly oxidized (t1/2 > or = 4 h) in the presence of NH2Cl formed by the FAC-NH3 reaction. Ozonation was sufficient to yield >99% depletion of 50 microg/L As(III) within 10 s of dosing 0.25 mg/L O3 (5.2 x 10(-6) M) to real waters containing <2 mg-C/L of DOC, while 0.8 mg/L O3 (1.7 x 10(-5) M) was sufficientfor a water containing 5.4 mg-C/L of DOC. NH3 had negligible effect on the efficiency of As(III) oxidation by O3, due to the slow kinetics of the O3-NH3 reaction at circumneutral pH. Time-resolved measurements of As(III) loss during chlorination and ozonation of real waters were accurately modeled using the rate constants determined in this investigation.     

The role of correspondence sections in post-publication peer review: A bibliometric study of general and internal medicine journals

Scientific journals claim that correspondence sections are for post-publication peer review. We compared the conditions for submission and the bibliometrics of letters-to-editors published in leading medical journals in 2002 and 2007 using journal-derived information and data from PubMed and Journal Citation Reports. The median time limit for letter submissions decreased from 6 to 3.5 weeks, the median word limit from 400 to 350. The median number of letters per published article was near one in both years. Only about half of the letters were followed by an author reply in either year. Electronic response systems were available for four journals in 2007.     

A scalable manufacturing process for flexible active‐matrix e‐paper displays

Abstract— A scalable manufacturing process for fabricating active‐matrix backplanes on low‐cost flexible substrates, a key enabler for electronic‐paper displays, is presented. This process is based on solution processing, ink‐jet printing, and laser patterning. A multilayer architecture is employed to enable high aperture ratio and array performance. These backplanes were combined with E Ink electrophoretic media to create high‐performance displays that have high contrast, are bistable, and can be flexed repeatedly to a radius of curvature of 5 mm.     

Interval Arithmetic on Multimedia Architectures

In this paper, we show how to implement interval arithmetic on multimedia architecture extensions. Due to the difficulties that current architectures have with the directed rounding modes the speed-up is rather modest. The study, nevertheless, may be helpful in future design of hardware extensions for interval arithmetic.     

Dissociation of memory retrieval and search processes: an event-related fMRI study

A cognitive task can often be subdivided into several subprocesses, which follow a specific temporal order. Here, we report an event-related functional magnetic resonance imaging (fMRI) experiment on memory search, in which the temporal onset of search in primary memory was varied relative to retrieval from secondary memory. Furthermore, previous behavioral studies demonstrated that search times in primary memory depend on the number of items in a memory set, whereas retrieval from secondary memory is a set-size independent process. We analyzed the dependency of the blood oxygenation level dependent (BOLD)-response on the temporal onset of memory search on the one hand and on memory set size on the other hand to differentiate the contribution of retrieval from secondary memory, maintenance in primary memory, item search in primary memory, and response-related processes. The timing of activation followed cue presentation bilaterally in the middle frontal gyri (Brodmann area (BA) 9,46) and the inferior parts of the precentral gyri (BA6). In all other regions of interest (ROI), supplementary motor area (SMA), posterior parietal cortex, antero-superior insula, and primary motor cortex, the onset of activation was delayed with delayed probe presentation, ruling out participation in retrieval from secondary memory. The amplitude of the BOLD-response increased with increasing memory set size in all ROI except primary motor cortex and left posterior parietal cortex. All areas with cue-associated BOLD onset, suggesting involvement in retrieval, showed prolonged BOLD activation, suggesting that they also support maintenance of the retrieved information.