Effects of α- and γ-tocopherols on formation of hydroperoxides and two decomposition products from methyl linoleate

The antioxidant effects of α-and γ-tocopherols (at 0, 10, 100, 500, and 1000 ppm) were evaluated in a model system based on the autoxidation of methyl linoleate in bulk for 4 d at 40°C. Samples were collected every 24 h and analyzed for the 9 cis,trans, 9 trans,trans, 13 cis,trans, and 13 trans,trans isomers of hydroperoxide, hydroxy, and ketodiene oxidation products by high-performance liquid chromatography. Results showed that both α- and γ-tocopherols are effective hydrogen donors as evidenced by their abilities to inhibit the formation of hydroperoxides, hydroxy compounds, and ketodienes and the cis,trans to trans,trans isomerization of hydroperoxides. Compared with γ-tocopherol, α-tocopherol was a more efficient antioxidant at very low concentrations (10 ppm) but a less efficient antioxidant at the high concentrations (100–1000 ppm). This paradoxical behavior is explained on the basis of differences in ease of hydrogen donation between the two tocopherol homologs. Although α-tocopherol shows some loss of efficiency with increasing concentration, it is not a prooxidant when compared to the control void of antioxidants.     

Influence of the synthesis parameters on the physico-chemical and catalytic properties of cerium oxide for application in the synthesis of diethyl carbonate

Synthesis of cerium (IV) oxide by means of room temperature precipitation method was carried out. The effect of preparation variables such as synthesis time, calcination temperature and pH of the solution on resulting CeO₂ properties was discussed. Moreover, the comparison of CeO₂ samples prepared in a static and rotation mode of synthesis is presented. The solid catalysts were characterized by means of X-ray powder diffraction, scanning electron microscopy, transmission electron microscope, nitrogen physisorption, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy using pyridine as a probe molecule and temperature programmed desorption of CO₂. Significant variations in physico-chemical properties of CeO₂ by varying the preparation conditions were observed. Furthermore, the catalytic performances of CeO₂ catalysts were compared in the synthesis of diethyl carbonate starting from ethanol and CO₂ using butylene oxide as a dehydrating agent. The dependence of CeO₂ properties on its catalytic activity is evaluated in detail.     

Characterization of Listeria monocytogenes isolates from the meat, poultry and seafood industries by automated ribotyping

A total of 564 Listeria monocytogenes isolates were characterized by automated ribotyping. The samples were taken from equipment, personnel and the environment after cleaning procedures and during food processing, as well as from raw materials and products from six meat, two poultry and five seafood processing plants located in the Faroe Islands, Finland, Iceland, Norway and Sweden. Altogether, 25 different ribotypes (RTs) were generated. Two RTs occurred in the samples from all three food sectors--meat, poultry and seafood. Four RTs occurred in meat and poultry plant samples and other four RTs occurred in meat and seafood plant samples. Five RTs occurred only in meat plant samples, five only in poultry plant samples and five only in seafood plant samples. Eight of the thirteen plants had their own in-house L. monocytogenes ribotype. There was geographical differences between the RTs, but no correlation between RTs and food sectors was detected. The discrimination power of automated ribotyping was satisfactory to trace the contamination sources in the food processing plants clearly indicating the sites at which improved cleaning procedures were necessary. In addition, it was possible to screen a large number of isolates with two instruments located at different institutes and to make a reliable combination of the results.     

Absolute transmission and separation properties of the gas-filled recoil separator RITU

The absolute transmission values of the RITU gas-filled recoil separator have been measured for several fusion evaporation products. Three different beams and several targets were used to create fusion evaporation residues in mass region A=170-190 mainly in neutron evaporation channels. Measured absolute transmission values from around 7% up to round about 90% have been observed for very asymmetric and symmetric reactions, respectively. For the reactions studied it was observed that the angular spread of products after the target and the angular acceptance of RITU determine the transmission probability relatively accurately. Magnetic rigidities and equilibrium charges of the product ions were seen to systemically decrease and increase, respectively, with increasing gas pressure. The comparison of observed equilibrium charges to various formulae is carried out. Clear minima of image width were found in case of asymmetric reactions as a function of gas pressure. Effects of the position of an additional movable beam stopper and the field strength of the first quadrupole magnet on transmission have been studied and are reported.     

The formation of a collaborative project identity in an infrastructure alliance project

Inter-organizational projects struggle to build a sense of joint belonging and a culture of cooperation. In evaluating the social processes of collaboration in inter-organizational projects, organizational identity is considered a core concept. To extend existing knowledge of how collaborative identity is formed in inter-organizational infrastructure projects, the study investigates how the specific characteristics of temporary organizations (time, team, task and context) influence identity formation activities. A case study of the first Finnish infrastructure alliance project identifies six key activities supporting the formation of collaborative project identity: (1) articulating a joint vision for collaborative project identity; (2) converging on mutual conceptions of collaborative project alliance philosophy; (3) attaining a shared collaborative mentality; (4) designing ways of working with multiple identities; (5) attaining distinctiveness and (6) legitimizing activities. The findings indicate that identity formation activities are context-dependent, and that the formation of organizational identity differs between temporary and permanent organizations. The findings illuminate how managers can build a collaborative project identity.     

Efficient weakest preconditions

Desired computer-program properties can be described by logical formulas called verification conditions. Different mathematically-equivalent forms of these verification conditions can have a great impact on the performance of an automatic theorem prover that tries to discharge them. This paper presents a simple weakest-precondition understanding of the ESC/Java technique for generating verification conditions. This new understanding of the technique spotlights the program property that makes the technique work.     

Kinetic Studies of Acetyl Group Migration between the Saccharide Units in an Oligomannoside Trisaccharide Model Compound and a Native Galactoglucomannan Polysaccharide

Acyl group migration is a fundamental phenomenon in carbohydrate chemistry, recently shown to take place also between two non-adjacent hydroxyl groups, across the glycosidic bond, in a β-(1→4)-linked mannan trisaccharide model compound. With the central mannoside unit containing acetyl groups at the O2 and O3 positions, the O2-acetyl was in the earlier study shown to migrate to O6 of the reducing end. Potential implications of the general acyl migration process on cell signaling events and plant growth in nature are intriguing open questions. In the present work, migration kinetics in this original trisaccharide model system were studied in more detail together with potential interactions of the model compound and the migration products with DC-SIGN lectin. Furthermore, we demonstrate here for the first time that similar migration may also take place in native polysaccharides, here represented by galactoglucomannan from Norway spruce.     

Zn2+ complexes of di- and tri-nucleating azacrown ligands as base-moiety-selective cleaving agents of RNA 3',5'-phosphodiester bonds: binding to guanine base

The ability of the dinuclear Zn2+ complex of 1,4-bis[(1,5,9-triazacyclododecan-3-yloxy)methyl]benzene (L(1)) to promote the cleavage of the phosphodiester bond of dinucleoside-3',5'-monophosphates that contain a guanine base has been studied over a narrow pH range from pH 5.8 to 7.2 at 90 degrees C. Comparative measurements have been carried out by using the trinuclear Zn2+ complex of 1,3,5-tris[(1,5,9-triazacyclododecan-3-yloxy)methyl]benzene (L(2)) as a cleaving agent and guanylyl-3',5'-guanosine (5'-GpG-3') as a substrate. The strength of the interaction between the cleaving agent and the starting material has been elucidated by UV spectrophotometric titrations. The speciation and binding mode have been clarified by potentiometric titrations with hydrolytically stable 2'-O-methylguanylyl-3',5'-guanosine and 1H NMR spectroscopic measurements with guanylyl-3',5'-guanosine. The results show that the guanine base is able to serve as a site for anchoring for the Zn2+-azacrown moieties of the cleaving agents L(1) and L(2), analogously to uracil base. The interaction is, however, weaker than with the uracil base and, hence, only the 5'-GpG-3' site (in addition to 5'-GpU-3' and 5'-UpG-3' sites) is able to markedly modulate the phosphodiester cleavage by the Zn2+ complexes of di- and trinucleating azacrown ligands containing an ether oxygen as a potential H-bond-acceptor site.     

Structure–Activity Relationships of 1-Benzoylazulenes at the OX1 and OX2 Orexin Receptors

We previously demonstrated the potential of di- or trisubstituted azulenes as ligands (potentiators, weak agonists, and antagonists) of the orexin receptors. In this study we investigated 27 1-benzoylazulene derivatives, uncovering seven potentiators of the orexin response on OX₁ and two weak dual orexin receptor agonists. For potentiators, replacement of the azulene scaffold by indole retained the activity of four out of six compounds. The structure–activity relationships for agonism and potentiation can be summarized into a bicyclic aromatic ring system substituted with two hydrogen-bond acceptors (1-position, benzoyl; 6-position, carboxyl/ester) within 7–8 Å of each other; a third acceptor at the 3-position is also well tolerated. The same pharmacophoric signature is found in the preferred conformations of the orexin receptor agonist Nag26 from molecular dynamics simulations. Subtle changes switch the activity between weak agonism and potentiation, suggesting overlapping binding sites.