Lipid analysis by matrix-assisted laser desorption and ionization mass spectrometry: A methodological approach

It has been hypothesized that protein factors may protect CpG islands from methyltransferase during development and that demethylation may involve protein-DNA interactions at demethylated sites. However, direct evidence has been lacking. In this study, demethylation at the EBNA-1 binding sites of the Epstein-Barr virus latent replication origin, oriP, was investigated by using human cells. Several novel findings are discussed. First, there are specific preferential demethylation sites within the oriP region. Second, the DNA sequence of oriP alone is not the target of an active demethylation process. Third, EBNA-1 binding is required for the site-specific demethylation in oriP. Interestingly, CpG sites adjacent to and between the EBNA-1 sites do not become demethylated. Fourth, demethylation of the first DNA strand in oriP at the EBNA-1 binding sites involves a passive (replication-dependent) mechanism. The second-strand demethylation appears to occur through an active mechanism. That is, EBNA-1 protein binding prevents the EBNA-1 binding sites from being remethylated after one round of DNA replication, and it appears that an active demethylase then demethylates these hemimethylated sites. This study provides clear evidence that protein binding specifies sites of DNA demethylation and provides insights into the sequence of steps and the mechanism of demethylation.     

Development and application of thermo-oxidation laboratory tests. Correlations with engine lubricant specifications

Laboratory simulation tests are an important stage in the selection of engine lubricants. Where these tests are brief and repeatable, they allow numerous studies and can provide a wide range of information. They are all the more valuable if they have a close degree of correlation with a specification test. The IIID high temperature oxidation test, the ME 1517 oxidation laboratory test and the Renault 30 diesel engine test are examples of specifications for the formulation of engine lubricants. The aim of the present study has been to find or develop a brief, repeatable laboratory test for these specifications and to establish a correlation between the test and the specification. Data obtained show satisfactory correlations between the TFOUT (Thin Film Oxygen Uptake Test) and the IIID sequence, the open oxidation laboratory test COST (24 h) and ME 1517 (192 h), and the ELF/ECL microcoking test and the Renault 30 turbo diesel test.     

Modeling of hydrogen explosion on a pressure swing adsorption facility

Computational fluid dynamic simulations have been performed in order to study the consequences of a hydrogen release from a pressure swing adsorption installation operating at 30 barg. The simulations were performed using FLACS-Hydrogen software from GexCon. The impact of obstruction, partial confinement, leak orientation and wind on the explosive cloud formation (size and explosive mass) and on explosion consequences is investigated. Overpressures resulting from ignition are calculated as a function of the time to ignition.     

A generic tool for cost estimating in aircraft design

A methodology to estimate the cost implications of design decisions by integrating cost as a design parameter at an early design stage is presented. The model is developed on a hierarchical basis, the manufacturing cost of aircraft fuselage panels being analysed in this paper. The manufacturing cost modelling is original and relies on a genetic-causal method where the drivers of each element of cost are identified relative to the process capability. The cost model is then extended to life cycle costing by computing the Direct Operating Cost as a function of acquisition cost and fuel burn, and coupled with a semi-empirical numerical analysis using Engineering Sciences Data Unit reference data to model the structural integrity of the fuselage shell with regard to material failure and various modes of buckling. The main finding of the paper is that the traditional minimum weight condition is a dated and sub-optimal approach to airframe structural design.     

Immunosuppression in paracoccidioidomycosis: T cell hyporesponsiveness to two Paracoccidioides brasiliensis glycoproteins that elicit strong humoral immune response

To assess human cellular immune response to paracoccidioidomycosis (PCM), lymphocyte proliferative responses to purified antigens from Paracoccidioides brasiliensis were determined in healthy persons previously infected by the fungus (positive donors), in healthy noninfected persons (controls), and in PCM patients. Affinity-purified gp70 and gp43, the two major antigens in humoral immune responses, were used. Both induced lymphocyte proliferation (gp43 species-specific) in positive donors but not in controls; healthy persons previously infected by Histoplasma capsulatum reacted to gp70 and not to gp43. A similar cross-reactivity in antibody response to gp70 was previously reported; however, antibody response to gp43 has been considered specific. Lymphocytes from PCM patients, who, unlike positive donors, have high levels of anti-gp43 and anti-gp70 antibodies, proliferated poorly with gp70 and gp43 but better with other stimuli. This dichotomy between humoral and cellular antigen-specific responses suggests a Th2 immune response in PCM, which may be related to failure to control the infection.     

Isolation,identification, and biological activity of trail-following pheromone of termiteTrinervitermes bettonianus (Sjöstedt) (Termitidae:Nasutitermitinae)

The principal compound which posseses trail-following activity at low concentration has been isolated from workers and from female alates of the grass feeding termiteTrinervitermes bettonianus. Male alates also produce the pheromone but in much smaller quantities than the female. The structure of the pheromone was determined as the diterpene hydrocarbon cembrene-A from spectra and microscale reaction data.     

DETERMINATION OF REPEATABILITY AND REPRODUCIBILITY OF EBC ACCEPTED METHODS. III—BARLEY ANALYSIS

Methods for barley analysis published in Analytics EBC, 4th ed. have been collaboratively tested by the European Brewery Convention Analysis Committee and other European laboratories involved in Barley analysis. Repeatability (r₉₅) and reproducibility (R₉₆) values are presented. The answers to a questionnaire sent to all participating laboratories are discussed.