129 research outputs found

    Evaluation of dissociated and steam-reformed methanol as automotive engine fuels

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    Dissociated and steam reformed methanol were evaluated as automotive engine fuels. Advantages and disadvantages in using methanol in the reformed rather than liquid state were discussed. Engine dynamometer tests were conducted with a four cylinder, 2.3 liter, spark ignition automotive engine to determine performance and emission characteristics operating on simulated dissociated and steam reformed methanol (2H2 + CO and 3H2 + CO2 respectively), and liquid methanol. Results are presented for engine performance and emissions as functions of equivalence ratio, at various throttle settings and engine speeds. Operation on dissociated and steam reformed methanol was characterized by flashback (violent propagation of a flame into the intake manifold) which limited operation to lower power output than was obtainable using liquid methanol. It was concluded that: an automobile could not be operated solely on dissociated or steam reformed methanol over the entire required power range - a supplementary fuel system or power source would be necessary to attain higher powers; the use of reformed mechanol, compared to liquid methanol, may result in a small improvement in thermal efficiency in the low power range; dissociated methanol is a better fuel than steam reformed methanol for use in a spark ignition engine; and use of dissociated or steam reformed methanol may result in lower exhaust emissions compared to liquid methanol

    Identification of HLA-DRPheβ47 as the susceptibility marker of hypersensitivity to beryllium in individuals lacking the berylliosis-associated supratypic marker HLA-DPGluβ69

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    BACKGROUND: Susceptibility to beryllium (Be)-hypersensitivity (BH) has been associated with HLA-DP alleles carrying a glutamate at position 69 of the HLA-DP β-chain (HLA-DPGlu69) and with several HLA-DP, -DQ and -DR alleles and polymorphisms. However, no genetic associations have been found between BH affected subjects not carrying the HLA-DPGlu69 susceptibility marker. METHODS: In this report, we re-evaluated an already described patient populations after 7 years of follow-up including new 29 identified BH subjects. An overall population 36 berylliosis patients and 38 Be-sensitization without lung granulomas and 86 Be-exposed controls was analysed to assess the role of the individual HLA-class II polymorphisms associated with BH-susceptibility in HLA-DPGlu69 negative subjects by univariate and multivariate analysis. RESULTS: As previously observed in this population the HLA-DPGlu69 markers was present in higher frequency in berylliosis patients (31 out of 36, 86%) than in Be-sensitized (21 out of 38, 55%, p = 0.008 vs berylliosis) and 41 out of 86 (48%, p < 0.0001 vs berylliosis, p = 0.55 vs Be-sensitized) Be-exposed controls. However, 22 subjects presenting BH did not carry the HLA-DPGlu69 marker. We thus evaluated the contribution of all the HLA-DR, -DP and -DQ polymorphisms in determining BH susceptibility in this subgroup of HLA-Glu69 subjects. In HLA-DPGlu69-negatives a significant association with BH was found for the HLA-DQLeu26, for the HLA-DRB1 locus residues Ser13, Tyr26, His32, Asn37, Phe47 and Arg74 and for the HLA-DRB3 locus clusterized residues Arg11, Tyr26, Asp28, Leu38, Ser60 and Arg74. HLA-DRPhe47 (OR 2.956, p < 0.05) resulting independently associated with BH. Further, Be-stimulated T-cell proliferation in the HLA-DPGlu69-negative subjects (all carrying HLA-DRPhe47) was inhibited by the anti-HLA-DR antibody (range 70–92% inhibition) significantly more than by the anti-HLA-DP antibody (range: 6–29%; p < 0.02 compared to anti-HLA-DR) while it was not affected by the anti-HLA-DQ antibody. CONCLUSION: We conclude that HLA-DPGlu69 is the primary marker of Be-hypersensitivity and HLA-DRPhe47 is associated with BH in Glu69-negative subjects, likely playing a role in Be-presentation and sensitization

    Study on the effects of nitrilotriproprionic acid and 4,5-dihydroxy-1,3-benzene disulphonate on the fractionation of beryllium in human serum using graphite furnace atomic absorption spectrometry

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    <p>Abstract</p> <p>Background</p> <p>Occupational exposure to beryllium may cause Chronic Beryllium Disease (CBD), a lung disorder initiated by an electrostatic interaction with the MHC class II human leukocyte antigen (HLA). Molecular studies have found a significant correlation between the electrostatic potential at the HLA-DP surface and disease susceptibility. CBD can therefore be treated by chelation therapy. In this work, we studied the effect of two complexing agents, nitrilotriproprionic acid (NTP) and 4,5-dihydroxy-1,3-benzene disulphonate (Tiron), on the fractionation of beryllium in human serum analysed by graphite furnace atomic absorption spectrometry (GFAAS).</p> <p>Results</p> <p>We found the average serum beryllium concentration of fourteen non-exposed individuals to be 0.53 (± 0.14) μg l<sup>-1</sup>, with 21 (± 3)% of the beryllium mass bound to the low molecular weight fraction (LMW), and 79 (± 3)% bound to the high molecular weight fraction (HMW). The addition of Tiron increased the beryllium mass in the HMW fraction, while NTP was not seen to have any influence on the fractionation of beryllium between the two fractions. NTP was, however, shown to complex 94.5% of the Be mass in the LMW fraction. The beryllium GFAAS detection limit, calculated as three times the standard deviation of 10 replicates of the lowest standard (0.05 μg L<sup>-1</sup>), was 6.0 (± 0.2) ng L<sup>-1</sup>.</p> <p>Conclusion</p> <p>The concentration of beryllium or its fractionation in human serum was not affected by sex or smoking habit. On average, three quarters of the beryllium in serum were found in the HMW fraction. Of the two ligands tested, only Tiron was effective in mobilising beryllium under physiological conditions, thus increasing the Be content in the HMW fraction.</p

    Post-traumatic anxiety associates with failure of the innate immune receptor TLR9 to evade the pro-inflammatory NFκB pathway

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    Post-traumatic anxiety notably involves inflammation, but its causes and functional significance are yet unclear. Here, we report that failure of the innate immune system Toll-like receptor 9 (TLR9) to limit inflammation is causally involved with anxiety-associated inflammation and that peripheral administration of specific oligonucleotide activators of TLR9 may prevent post-traumatic consequences in stressed mice. Suggesting involvement of NFκB-mediated enhancement of inflammatory reactions in the post-traumatic phenotype, we found association of serum interleukin-1β increases with symptoms severity and volumetric brain changes in post-traumatic stress disorder patients. In predator scent-stressed mice, the moderate NFκB-activating oligonucleotides mEN101 and its human ortholog BL-7040, but not the canonic NFκB activator oligonucleotide ODN1826, induced anxiolytic effects. In stressed mice, peripherally administered mEN101 prevented delayed stress-inducible serum interleukin-1β increases while limiting stress-characteristic hippocampal transcript modifications and the anxiety-induced EGR1-mediated neuronal activation. Attesting to the TLR9 specificity of this response, BL-7040 suppressed NFκB-mediated luciferase in transfected cells co-expressing TLR9, but not other TLRs. Furthermore, TLR9−/− mice were mEN101 and BL-7040 resistant and presented unprovoked anxiety-like behavior and anxiety-characteristic hippocampal transcripts. Our findings demonstrate functional relevance of TLR9 in protecting stressed mammals from overreacting to traumatic experiences and suggest using oligonucleotide-mediated peripheral TLR9 activation to potentiate the innate immune system and prevent post-traumatic inflammation and anxiety

    Development of a test facility for the experimental evaluation of liquid and gaseous automotive engine fuels

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    Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Bibliography: leaves 64-67.Not availabl
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