An investigation of the effects of polymer binder compositional variables on the corrosion control of aluminum alloys using magnesium-rich primers

It has recently been shown that magnesium (Mg) particles possessing a thin oxide surface layer can be used to produce primers that provide corrosion protection to aluminum (Al) alloys through a galvanic coupling mechanism. In addition to the Mg particles, polymer binder properties also affect corrosion protection. As a result, the effects of compositional variables associated with a two-component epoxy binder system on the ability of Mg-rich primers to protect an aerospace Al alloy were determined. The variables investigated were epoxy resin molecular mass, curing agent functionality, epoxy/NH ratio, and Mg content. All of the variables investigated had a significant effect on coating system performance and an optimized coating composition was identified that showed very good corrosion protection for at least 3,000 h of ASTM B117 salt spray exposure.     

Synthesis and antimicrobial activity of quaternary ammonium-functionalized POSS (Q-POSS) and polysiloxane coatings containing Q-POSS

An array of quaternary ammonium-functionalized POSS (Q-POSS) compounds were synthesized and their antimicrobial properties toward the Gram-negative bacterium, Escherichia coli, and the Gram-positive bacterium, Staphylococcus aureus, determined in aqueous solution. Using Q-POSS compositions that exhibited broad spectrum antimicrobial activity in solution, the utility of the Q-POSS compounds as an antimicrobial additive for polysiloxane coatings was determined. The results of the investigation showed that Q-POSSs possessing a relatively low extent of quaternization and longer alkyl chain lengths provided the highest antimicrobial activity in solution. For polysiloxane coatings containing Q-POSS molecules as an antimicrobial additive, coating surface energy, surface morphology, and antimicrobial properties were found to be strongly dependent on Q-POSS composition. Coatings based on Q-POSSs possessing the lowest extent of quaternization displayed antimicrobial activity while analogous coatings produced using Q-POSSs possessing the highest extent of quaternization showed no antimicrobial activity. The lack of antimicrobial activity exhibited by coatings possessing Q-POSSs with a relatively high extent of quaternization was attributed to agglomeration of Q-POSS molecules through the formation of intermolecular interactions involving the quaternary ammonium moieties. Agglomeration would be expected to reduce diffusivity and inhibit interaction of the Q-POSS molecules with microbial cells.     

RebG- and RebM-catalyzed indolocarbazole diversification

Rebeccamycin and staurosporine represent two broad classes of indolocarbazole glycoside natural products with antitumor properties. Based upon previous sequence annotation and in vivo studies, rebG encodes for the rebeccamycin N-glucosyltransferase, and rebM for the requisite 4'-O-methyltransferase. In the current study, an efficient in vivo biotransformation system for RebG was established in both Streptomyces lividans and Escherichia coli. Bioconversion experiments revealed RebG to glucosylate a set of indolocarbazole surrogates, the products of which could be further modified by in vitro RebM-catalyzed 4'-O-methylation. Both RebG and RebM displayed substrate promiscuity, and evidence for a remarkable lack of RebG regioselectivity in the presence of asymmetric substrates is also provided. In the context of the created indolocarbazole analogues, cytotoxicity assays also highlight the importance of 4'-O-methylation for their biological activity.     

Development of primer and probe sets for the detection of plant species in honey

An objective of workpackage 3 within the European Research Project “TRACE” was the identification of PCR markers for the detection of plant species related to honey. Within the project “Miel de Corse”, a protected designation of origin (PDO) honey and “Miel de Galicia”, a protected geographical indication (PGI) honey as well as German and English honeys were analysed. Beside the development of plant species specific real-time PCR systems a method has been established for the detection of DNA derived from plant species in general.     

Atomically Dispersed Transition Metals on Carbon Nanotubes with Ultrahigh Loading for Selective Electrochemical Carbon Dioxide Reduction

Single‐atom catalysts (SACs) are the smallest entities for catalytic reactions with projected high atomic efficiency, superior activity, and selectivity; however, practical applications of SACs suffer from a very low metal loading of 1–2 wt%. Here, a class of SACs based on atomically dispersed transition metals on nitrogen‐doped carbon nanotubes (MSA‐N‐CNTs, where M = Ni, Co, NiCo, CoFe, and NiPt) is synthesized with an extraordinarily high metal loading, e.g., 20 wt% in the case of NiSA‐N‐CNTs, using a new multistep pyrolysis process. Among these materials, NiSA‐N‐CNTs show an excellent selectivity and activity for the electrochemical reduction of CO₂ to CO, achieving a turnover frequency (TOF) of 11.7 s^?1 at ?0.55 V (vs reversible hydrogen electrode (RHE)), two orders of magnitude higher than Ni nanoparticles supported on CNTs.     

In Clouds Shall We Trust?

Cloud computing will become ubiquitous, but what we can do to improve our ability to provide users and providers of cloud computing with trust in the software services and infrastructure that make up the cloud. In this article we touch on issues of the transparency, changing expectations and uses, architecture, and amorphous nature of cloud computing.     

Sex attractant for three species of the genusOncocnemis: O. chandleri (Grt.),O. cibalis (Grt.), andO. mackiei (B. & Benj.) (Lepidoptera: Noctuidae)

Oncocnemis chandleri, O. cibalis, andO. mackiei were attracted to chemically baited traps in the field. In all three cases, (5E,7Z)-dodecadienyl acetate was a key component for attraction. Attraction ofO. chandleri to traps baited with the (5E,7Z)-dodecadienyl acetate was inhibited by addition of (Z)-7-dodecenyl acetate.O. cibalis required both (5E,7Z)-dodecadienyl acetate and (Z)-7-dodecenyl acetate for attraction. Electroantennogram responses for the three species are also reported.     

Aorto-coronary bypass

OBJECTIVES: Saphenous grafts used for coronary artery bypass are classically dissected via a continuous incision of the leg, the thigh or both. Recently, a new video-surgery technique has been introduced in an attempt to reduce the trauma of saphenous vein dissection. The aim of this work was to evaluate the possible benefits of this new technique compared with classical dissection. PATIENTS AND METHODS: Sixty patients requiring coronary artery bypass grafts were included in this study and randomly divided into two groups. In group I (30 patients) the saphenous vein was dissected according to the classical technique. The video-surgery technique was used for the other 30 patients in group II. The two groups were not significantly different for mean age, sex ratio, or history of diabetes or lower limb arteriopathy. The same number of bypasses was performed in both groups (2.6 +/- 0.7). Outcome was compared for: dissection related complications (hematomas, infections), length of the skin incision over the length of the dissected vein, duration of the dissection procedure, and post-operative pain. RESULTS: A leg incision was used in 28 cases out of 30 cases in both groups. The length of the saphenous vein dissected was 27.6 cm in group I and 21.8 cm in group II. The length of the skin incision was 27 cm in group I and only 4.7 cm in the video-surgery group II, giving an incision/vein ratio of 97% and 21% respectively. Operative time was however 37.9 min for group I and 48.5 min for group II. There was no significant difference between the groups for hematoma formation or infection but the patients in the video-surgery group experienced less post-operative pain. CONCLUSION: Besides an improvement in the esthetic result, video-surgery dissection of the saphenous vein reduces post-operative pain at the cost of a slightly longer operative procedure.