The prediction of fatty acid structure from selected ions in electron impact mass spectra of fatty acid methyl esters

The possibility of fatty acid identification from ions in the mass region of 50–110 amu in electron impact mass spectra has been studied by application of various multivariate techniques. The focus has mainly been on the prediction of the number of double bonds in methylene‐interrupted polyunsaturated fatty acids isolated from marine lipids. The number of double bonds in these fatty acids could be predicted with high accuracy, both by partial least squares regression on all ions in this region, and by multiple linear regressions on selected subsets of 5–6 ions. The subsets with optimal predictive power have been found, and the ability to distinguish between methylene interrupted polyunsaturated fatty acids and other fatty acids have also been evaluated.     

Human regulatory subunit RI beta of cAMP-dependent protein kinases: expression, holoenzyme formation and microinjection into living cells

The human regulatory subunit RI beta of cAMP-dependent protein kinases was expressed in Escherichia coli as a fusion protein with glutathione S-transferase. Purification was performed by affinity chromatography on glutathione-agarose beads after cleavage with thrombin. The human recombinant RI beta protein migrated at 55 kDa on SDS-PAGE and displayed immunoreactivity with an anti-human RI beta antiserum. Furthermore, the purified recombinant RI beta protein was shown to exist as a dimer that was able to form holoenzyme with the catalytic subunit C alpha. The rate of RI beta 2C alpha 2 holoenzyme formation was faster in the presence than in the absence of MgATP. The kinase activity measured before and after adding cAMP to the holoenzyme showed that the presence of cAMP resulted in holoenzyme dissociation and release of active C alpha-subunit, due to cAMP binding to RI beta. Compared to a RI alpha 2C alpha 2 holoenzyme, the RI beta 2C alpha 2 holoenzyme exhibited a more than twofold higher sensitivity to cAMP. The subcellular localization of RI beta was analyzed in quiescent REF-52 fibroblasts and Wistar rat thyroid (WRT) cells after microinjection of fluorescently labeled proteins into the cytoplasm. A cytoplasmic distribution was observed when free RI beta was injected, whereas free C alpha injected into the cytoplasm appeared in the nucleus. When holoenzymes with labeled RI beta and unlabeled C alpha, or unlabeled RI beta and labeled C alpha, were injected, unstimulated cells showed fluorescence in the cytoplasm of both cell types. REF-52 cells stimulated with 8-bromo-cAMP (8-Br-cAMP) and WRT cells treated with thyrotropin (TSH) showed fluorescence mainly in the cytoplasm when RI beta was the labeled subunit of the in vivo dissociated holoenzyme. In contrast, nuclear fluorescence was evident from the release and translocation of labeled C alpha from the holoenzyme complex after stimulation with 8-Br-cAMP or TSH.     

Capillary pressure scanning curves by the micropore membrane technique

Experimental procedures have been developed for capillary pressure hysteresis measurements. Capillary drainage and imbibition bounding curves (complete bounding cycle) and a number of scanning curves have been measured for a water-wet Berea core and an oil-wet reservoir core by the micropore membrane technique. The curves are measured both with stepwise and continuous change of the differential pressure. A continuous and slow change of capillary pressure gives considerable savings in experimental time. Reversibility of scanning curves is observed for the Berea core when the range of saturation reversal is less than 5% and may be explained by a pinning effect. The oil-wet reservoir core, however, exhibits a hysteresis loop even for this small saturation range. For saturation reversals in excess of 5%, the scanning curves for both samples form closed loops that are similar in shape to the bounding loop, i.e., for each sample, all hysteresis loops have the same shape but different sizes. This fact may be used to improve the algorithm for hysteresis modelling.     

Scaling of the viscoelasticity of highly filled carbon black polyethylene composites above the melting point

Different types of linear low-density polyethylene and ethylene butylacrylate copolymers were mixed with various types of carbon black in amounts between 25 and 40% by weight. Viscoelastic properties were measured using dynamic mechanical analysis applying a frequency sweep. Typically, the complex modulus approaches asymptotically a constant value at small frequencies, which is referred to as ‘yield modulus’. These results were analysed using a scaling approach according to which the complex modulus and the frequency are normalised by the yield modulus and the quotient of the yield modulus and the polymer viscosity, respectively. Thus a master curve is achieved for nearly all samples independent of the polymer and carbon black type and loading. A similar scaling behaviour has been observed earlier for differently concentrated suspensions of carbon black in Newtonian liquids, but not for filled polymers and different carbon blacks. Thus, contributions from polymer and carbon black to the compounds' viscoelastic properties are discussed.     

Continuous quality improvement in primary care: what's happening?

OBJECTIVES: Despite much health care interest in quality and Continuous Quality Improvement, there is little quantitative information about it. The purpose of this study was to measure the attitudes, activities, and organizational cultures concerning Continuous Quality Improvement in a group of Midwestern primary care clinics. METHODS: Three surveys of the clinicians, nurses, and other staff in 44 primary care clinics in the metropolitan area of Minneapolis and St. Paul were conducted. These surveys assessed: (1) attitudes about quality improvement, (2) previous efforts in these clinics to use process improvement teams, and (3) the extent to which the clinics' organizational cultures were perceived as supporting quality. The Provider Attitude Survey was completed by clinicians and nurses; the Process Improvement Progress was completed by members of the best Continuous Quality Improvement teams, if any; and the Quality Systems Inventory was completed by all personnel. RESULTS: Most of the clinical personnel reported support for various Continuous Quality Improvement concepts, but their understanding and experience were limited. Only 20 (45%) clinics had had at least one Continuous Quality Improvement team in the past, only five of the 12 teams with adequate information had completed an improvement cycle, and only seven reported improving a process with it. The mean clinic scores for quality culture were no better than those in other types of organizations. CONCLUSIONS: Despite relatively favorable attitudes and some Continuous Quality Improvement activities, there appears to be a need to help clinics build skill and experience for the required care improvements.     

Evaluation of quarternary aggregate resources in Norway

The paper refers to some results of recent research in Norway on aggregate/concrete interaction. The objective has been to establish criteria for classification, based on knowledge of the geological origin of the aggregates. The evaluation system developed incorporates an automatic data processing information system and a new method of mineralogical quality classification of sand aggregates. The latter refers primarily to the properties of aggregates determining the water requirement and strength of concrete. The system has been used for evaluating a large number of Quaternary aggregate deposits throughout the country, and the results have been correlated with relevant concrete testing.     

Evaluation of Chinese projects and comparison with Norwegian projects

Project work in developing and emerging economies is complicated and unpredictable. It would be of great help to equip project managers with an easily applicable tool to assess whether the project is on the right track or not. A Project Evaluation Scheme (PEVS) has earlier been used on Norwegian projects. Data from 89 Chinese projects has been collected using the scheme. This article analyses the Chinese data and compares them to the Norwegian findings. The Chinese projects are scoring higher in all areas investigated, except on informal contacts. Particularly high were goal setting, overall planning and control execution. The Chinese projects achieve their goals and are regarded as a success by all participants. They should improve in project closeout work. The article discusses the reasons for differences between Chinese and Norwegian projects, ranging from differences in perception regarding the questionnaire, to the possibility that Chinese projects in fact are better. The qualities of activity execution are found to be the most important factor in predicting project success. PEVS is proven to be applicable to Chinese projects, yet further customisation is needed.     

Impedance modelling of air electrodes in alkaline media

A mathematical model of the impedance response of porous air electrodes in alkaline solutions, based on flooded agglomerate theory, was developed. The model results provides insight into characteristic features of the impedance spectra according to the relative rate of the various reactions and mass transfer processes occurring. The modelled spectra where dissolution, transport and reaction of oxygen dominates the impedance are close to ideal semicircles. With increasing contribution from ionic transport in the solution inside the pores, two distinct features occur, namely the appearance of a 45° branch at high frequencies, and an inductive loop at low frequenices. Examples from the literature where inductive loops occurs are given.     

Methylmercury Increases and Eicosapentaenoic Acid Decreases the Relative Amounts of Arachidonic Acid-Containing Phospholipids in Mouse Brain

The membrane phospholipid composition in mammalian brain can be modified either by nutrients such as dietary fatty acids, or by certain toxic substances such as methylmercury (MeHg), leading to various biological and toxic effects. The present study evaluated the effects of eicosapentaenoic acid (EPA) and MeHg on the composition of the two most abundant membrane phospholipid classes, i.e., phosphatidylcholines (PtdCho) and phosphatidylethanolamines (PtdEtn), in mouse brain by using a two‐level factorial design. The intact membrane PtdCho and PtdEtn species were analyzed by liquid chromatography–mass spectrometry. The effects of EPA and MeHg on the PtdCho and PtdEtn composition were evaluated by principal component analysis and ANOVA. The results showed that EPA and MeHg had different effects on the composition of membrane PtdCho and PtdEtn species in brain, where EPA showed strongest impact. EPA led to large reductions in the levels of arachidonic acid (ARA)‐containing PtdCho and PtdEtn species in brain, while MeHg tended to elevate the levels of ARA‐containing PtdCho and PtdEtn species. EPA also significantly increased the levels of PtdCho and PtdEtn species with n‐3 fatty acids. Our results indicate that EPA may to some degree counteract the alterations of the PtdCho and PtdEtn pattern induced by MeHg, and thus alleviate the MeHg neurotoxicity in mouse brain through the inhibition of ARA‐derived pro‐inflammatory factors. These results may assist in the understanding of the interaction between MeHg, EPA and phospholipids, as well as the risk and benefits of a fish diet.     

LaMg11 with a giant unit cell synthesized by hydrogen metallurgy: Crystal structure and hydrogenation behavior

We have successfully applied a hydrogen metallurgy synthesis to yield LaMg_12?x intermetallic at 500 °C. During a vacuum thermal desorption from the LaH₃–MgH₂ nanocomposite prepared by reactive ball milling in H₂, hydrogen desorption from the La dihydride occurred via a mechanism of cooperative phase transformation at temperatures being 400° lower than the desorption from pure LaH₂. The crystal structure of the intermetallic was determined by synchrotron X-ray diffraction (SR XRD). The orthorhombic LaMg_12?x has a giant unit cell, the volume of which exceeds 8000 Å³. In situ SR XRD studies showed the fine details of the hydrogen desorption process with several parallel and consecutive transformation steps.