Oxidation of methyl linoleate in the presence of lignin

The overall aim of this study is to develop new wood modifications using vegetable oils to obtain improved durability of wood materials in an environmentally friendly way. Nuclear magnetic resonance (NMR) and Fourier-transform infrared (FT-IR) spectroscopies were used to study oxidation and possible chemical coupling reactions between polyunsaturated fatty acids and model lignin compounds in order to better understand the interactions between oxidatively drying systems such as vegetable oils or alkyds with the lignin part in wood. This was done by studying mixtures of different model lignin compounds and methyl linoleate. The oxidation process was analyzed at 70 °C both in methyl linoleate alone and in combination with 20 wt% of lignin model compounds. The effects of those compounds on the oil polymerization processes were monitored by NMR (both ¹³C and ¹H experiments) and the domain specific reactivity and patterning were then combined with FT-IR data. No covalent bonds having formed between the oil and the model compounds were detected by combination of several ¹³C/¹H 2D NMR methods. From the spectra, the oxidation degrees of model compounds were calculated, and for some lignin model compounds alcohols were oxidized to carbonyls during the process. Those results were in excellent agreement with FT-IR data and oxidation mechanisms were proposed. The combination of both analytical techniques was necessary to have a better understanding of these systems: NMR demonstrated the absence of chemical bond and quantified oxidation degree of model lignin molecules while FT-IR focused on oil oxidation.     

Multifunctional folded polypeptides from peptide synthesis and site-selective self-functionalization--practical scaffolds in aqueous solution

The site selectivity of His-mediated lysine and ornithine side-chain acylation in a designed four-helix bundle protein scaffold was mapped by reaction of several polypeptides with one equivalent of mono-p-nitrophenyl fumarate in aqueous solution at pH 5.9 and room temperature followed by an analysis of the degrees and sites of acylation. Integration of the HPLC chromatograms of the acylated polypeptides and trypsin cleavage followed by mass spectrometry analysis of the tryptic fragments provided the experimental evidence. Based on these and previously published results a strategy was developed for the site-selective and stepwise incorporation of three residues into a folded polypeptide in aqueous solution at room temperature. The first substituent was incorporated by reaction of a 1.7-fold excess of the corresponding active ester with the polypeptide at pH 5.9, the second substituent was introduced in a 3-fold excess after the pH value was raised to 8, and the third substituent was incorporated by reaction of a 10-fold excess with the polypeptide at pH 5.9. No intermediate steps of purification were taken and the overall yield was 30 % or more. Examples of the substituents included are carbohydrates, an enzyme inhibitor, a fumarate, and an acetate group. The introduction of different substituents into three individually addressable positions in a stepwise, efficient, and controllable reaction demonstrates that designed folded polypeptides are practically useful scaffolds that can be functionalized by using very simple chemistry in aqueous solution. Predicted applications include designed receptors, biosensors, and molecular devices.     

A Metrics Framework to Drive Application Security Improvement

This installment of Building Security In presents metrics that can help quantify the impact that process changes in one life-cycle phase have on other phases.     

Relation of spatial learning of rats in the Morris water maze task to the number of viable CA1 neurons following four-vessel occlusion.

Male Wistar rats were tested in the Morris water maze task 1 wk after 6, 9, or 12 min of transient global ischemia. The 9-min and 12-min ischemia groups were significantly impaired in the acquisition and the reversal experiment. A systematic counting of CA1 neurons in the whole hippocampal formation revealed a unilateral number of CA1 neurons of 286,000 in the sham group, of which two-thirds were located in the dorsal hippocampus. The ischemia groups showed a significant decline in the number of dorsal CA1 neurons, whereas only the 12-min ischemia group showed a significant but minor decline (10–25%) in the number of ventral CA1 neurons. A correlation analysis showed that the escape distance declined with increasing number of viable CA1 neurons, but poor correlation coefficients were obtained. Thus, some of the ischemic rats with even very few viable CA1 neurons in the dorsal hippocampus were capable of performing this spatial learning task at sham-group level. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Elektronische Archive in virtuellen Organisationen Gestaltung im Spannungsfeld von Kooperation und Konkurrenz

Virtuelle Organisationen stellen ein relativ neues Anwendungsfeld der Informatik dar. Aus den Besonderheiten dieses Organisationstypus ergeben sich neue Gestaltungsaufgaben. In diesem Aufsatz wird anhand einer Fallstudie aus der Stahlindustrie gezeigt, in welch komplexer Weise Kooperation und Konkurrenz in virtuellen Organisationen miteinander verwoben sein kann. Daraus ergeben sich Konsequenzen für die Gestaltung der Zugriffskontrolle auf elektronische Archive, wenn diese für die organisationsübergreifende Kooperation in einer virtuellen Organisation genutzt werden. Basierend auf diesen Erkenntnissen stellt der in der n?chsten Ausgabe des Informatik Spektrum erscheinende zweite Teil des Aufsatzes eine komponentenbasierte Anwendung zur Zugriffskontrolle in virtuellen Organisationen vor.     

Musculoskeletal, visual and psychosocial stress in VDU operators before and after multidisciplinary ergonomic interventions. A 6 years prospective study—Part II

A prospective epidemiological field study covering a 2 years period has earlier been published (Appl. Ergon. (1998) 29(5) 335). The study has a parallel group design with two intervention groups (T and S) and one control group (C) of Visual Display Unit (VDU) operators. The present paper covers the period from 2 to 6 years of the study. After 3.5 years, the C group got the same intervention in terms of new lighting system, new workplaces and at last an optometric examination and corrections if needed. The C group reported a significant reduction in visual discomfort after interventions while the two groups (T and S) continued to report significant reduction of visual discomfort after 6 years. By supporting the forearm on the table top, the C group reported significant reduction of shoulder and neck pain while the T group reported significant reduction in shoulder and back pain after 6 years. Organizational and psychosocial factors at work and outside work did not show any significant changes during the study period.     

Multiple Connectivity and Spectrum Access Utilisation in Heterogeneous Small Cell Networks

In the context of heterogeneous and small cell networks, users will have the possibility to connect to multiple radio access (RA) carriers that will be available by a dense deployment of RA infrastructure consisting of high-power and low-power access nodes. Determining which RAs a user should be associated with and select from, for its downlink transmissions, depends on the long-term and short-term data rates that these RAs may offer to the user. In this study the multi-RA association and utilisation is decomposed into a multi-RA to user association problem that assigns multiple RAs to users, and a multi-RA selection problem that determines which of the assigned RAs should be used at any time for the user transmissions. As a solution to the first problem, we propose a distributed dual-based spectrum access scheme (DSA) that considers multi-connectivity, whilst, the second problem is solved by means of a heuristic multi-RA selection scheme that utilise different multi-radio transmit diversity (MRTD) schemes while taking into account different inter-cell interference coordination (ICIC) schemes. Our two-step approach is evaluated by means of simulations which demonstrate cell-edge user throughput performance improvements that exceed 100 % when the multi-connectivity DSA is employed. Further significant user rate and energy efficiency improvements up to 69 and 38 % respectively can be achieved when MRTD is combined with ICIC.