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The direct synthesis of hydrogen peroxide (H 2 O 2 ) from molecular H 2 and O 2 over Au−Pd/TiO 2 catalysts prepared using a modified impregnation methodology is studied. Initially we investigated the role of the Au:Pd ratio on the catalytic activity toward H 2 O 2 formation and its subsequent degradation under conditions that have previously been found to be optimal for the formation of H 2 O 2 using high pressure reactants and low temperatures. Subsequently, we have conducted a detailed study of H 2 O 2 synthesis under ambient conditions which are both more challenging for achieving high yields of H 2 O 2 but more likely to be used for future industrial applications.

The adequate management of cerebral perfusion pressure (CPP) continues to be a controversial issue in head-injured patients. The purpose of our study was to test two hypotheses. The first was that in patients with a CPP below 70 rom Hg, oxygen delivery is compromised and that therefore signs of tissue hypoxia would be reflected in low Pti02 measurements. The second hypothesis was that manipulating mean arterial blood pressure to increase CPP improves oxygen delivery, particularly in patients with a CPP below 70 rom Hg.Twenty-five moderately or severely head-injured patients were included in the study. In all of them Pti02 was monitored in the noninjured hemisphere using the Licox system (GMS, Kiel-Mielkendorf, Germany). Arterial hypertension was induced with phenylephrine 29 times. To quantify the effect of increasing mean arterial blood pressure (MABP) on oxygen delivery to the brain, the Pti02-BP index was calculated (Pti02-BP index = APti02/AMABP). In 16 tests (55%) baseline CPP was above or equal to 70 rom Hg and in the remaining 13 (45%) it was below 70 mm Hg. Mean increase in MABP after phenylephrine was 23.7 ± 10.2 rom Hg. Mean Pti02 was 29.5 ± 14.7 rom Hg in patients with a basal CPP of below 70 rom Hg and 28.9 ± 10.6 rom Hg in patients in the high CPP group. These differences being not statistically significant. The Pti02-BP index was 0.29 ± 0.23 in patients with a basal CPP of below 70 rom Hg and in patients with a CPP of above 70 rom Hg this index was 0.16 ± 0.11 Hg. These differences were not statistically significant (Student's t-test, P = 0.09). In our study a low Pti02 was not observed in patients with marginally low CPPs (48-70 mm Hg) and readings below 15 rom Hg were observed in cases with both normal or supranormal CPPs. We conclude that episodes oflow Pti02 could not be predicted on the basis of CPP alone. On the other hand, raising CPP did not increase oxygen availability in the majority of cases, even if the CPP was markedly improved.

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BackgroundHaematuria has been traditionally considered as a benign hallmark of some glomerular diseases; however new studies show that haematuria may decrease renal function.ObjectiveTo determine the influence of haematuria on the rate of chronic kidney disease (CKD) progression in 71 proteinuric patients with advanced CKD (baseline eGFR <30 mL/min) during 12 months of follow-up.ResultsThe mean rate of decline in eGFR was higher in patients with both haematuria and proteinuria (haemoproteinuria, HP, n=31) than in patients with proteinuria alone (P patients, n=40) (-3.8±8.9 vs 0.9±9.5 mL/min/1.73m2/year, p<0.05, respectively). The deleterious effect of haematuria on rate of decline in eGFR was observed in patients <65 years (-6.8±9.9 (HP) vs. 0.1±11.7 (P) mL/min/1.73m2/year, p<0.05), but not in patients >65 years (-1.2±6.8 (HP) vs. 1.5±7.7 (P) mL/min/1.73m2/year). Furthermore, the harmful effect of haematuria on eGFR slope was found patients with proteinuria >0.5 g/24 h (-5.8±6.4 (HP) vs. -1.37± 7.9 (P) mL/min/1.73m2/year, p<0.05), whereas no significant differences were found in patients with proteinuria < 0.5 g/24 h (-0.62±7.4 (HP) vs. 3.4±11.1 (P) mL/min/1.73m2/year). Multivariate analysis reported that presence of haematuria was significantly and independently associated with eGFR deterioration after adjusting for traditional risk factors, including age, serum phosphate, mean proteinuria and mean serum PTH (β=-4.316, p=0.025).ConclusionsThe presence of haematuria is closely associated with a faster decrease in renal function in advanced proteinuric CKD patients, especially in younger CKD patients with high proteinuria levels; therefore this high risk subgroup of patients would benefit of intensive medical surveillance and treatment.