Hydrogen can be produced by catalytic steam reforming of bio-oil or its fractions. Bio-oil is a complex
mixture of a large number of compounds derived from fast pyrolysis of biomass. Acetol has been selected as
a model compound. Steam reforming of acetol has been studied in a fluidized bed reactor using coprecipitated
Ni−Al catalysts, some promoted with lanthanum and cobalt. Noncatalytic experiments have been performed
from 450 to 650 °C. Catalytic experiments have been carried out at 600 and 650 °C in order to analyze the
influence of the catalyst weight/acetol flow rate (W/m
Ac) ratio on gas yields. The influence of the steam to
carbon molar (S/C) ratio and the catalyst composition on gas yields has also been studied. The presence of
the catalyst increases H2, CO2, and total gas yields while CH4, CO, and C2 yields decrease. An increase in the
S/C ratio at 650 °C increases H2, CO2, and total gas yields and carbon conversion to gas. The presence of
lanthanum in Ni−Al coprecipitated catalysts increases CH4, CO2, C2, and total gas yields as well as carbon
conversion to gas. Ni−Co−Al catalysts present the lowest values of carbon conversion to gas. Hydrogen
yields obtained with the catalysts tested follow this sequence: Ni−Al = Ni−Co−Al (Co/Ni = 0.25) >
Ni−Co−Al (Co/Ni = 0.025) > Ni−Al−La (4 wt % La2O3) > Ni−Al−La (8 wt % La2O3) > Ni−Al−La (12
wt % La2O3).
3-Hydroxy-3-methylglutaric aciduria is a rare autosomal recessive genetic disorder that affects ketogenesis and L-leucine catabolism. The clinical acute symptoms include vomiting, convulsions, metabolic acidosis, hypoketotic hypoglycaemia and lethargy. To date, 33 mutations in 100 patients have been reported in the HMGCL gene. In this study 10 new mutations in 24 patients are described. They include: 5 missense mutations: c.109G>A, c.425C>T, c.521G>A, c.575T>C and c.598A>T, 2 nonsense mutations: c.242G>A and c.559G>T, one small deletion: c.853delC, and 2 mutations in intron regions: c.497+4A>G and c.750+1G>A. Two prevalent mutations were detected, 109G>T (E37X) in 38% of disease alleles analyzed and c.504_505delCT in 10% of them. Although patients are mainly of European origin (71%) and mostly Spanish (54%), the group is ethnically diverse and includes, for the first time, patients from Pakistan, Palestine and Ecuador. We also present a simple, efficient method to express the enzyme and we analyze the possible functional effects of missense mutations. The finding that all identified missense mutations cause a >95% decrease in the enzyme activity, indicates that the disease appears only in very severe genotypes."
The effect of t-butyl hydroperoxide (t-BOOH) on the induction of the Major Histocompatibility Complex (MHC) class I genes has been studied in two cell clones (B9 and G2) of the methylcholanthrene-induced murine fibrosarcoma GR9. These two clones were selected based on their different biological and biochemical behavior specially related to their tumor induction capability when injected into a BALB/c mouse. t-BOOH (0.125 mM) induced the expression of H-2 molecules in both cell clones. In B9 cell clone, in which MHC basal expression is very low or absent, t-BOOH significantly induced H-2Kd, H-2Dd and H-2Ld molecules. In G2 cell clone the expression of MHC class I genes was also enhanced by the xenobiotic, the effect being especially significant on the H-2Ld molecule which is not expressed under basal conditions. H-2 molecules expression was accompanied by the activation of the transactivator factor NF kappa B. These results suggest that oxidative stress may modulate the antigen expression of tumor cells and thus the immune response of the host organism. Basal levels of oxidative parameters, such as anti-oxidant enzymes, malondialdehyde (MDA) and the DNA damaged base 8-hydroxy-2'-deoxyguanosine (8-OHdG), showed differences between the two fibrosarcoma cell clones.
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