Anti-oxidative enzymes in pulmonary emphysemia

ln study anti-oxidative enzymes (Cat, G-Px, G-red, G-6PD11 and GSH) in patients with pulmonary emphysema, we analyzed the blood samples taken from 20 patients with global respiratory failure (10 males, mean age 56+-7.5 yis, and 10 females, mean age 60±5yrs). All patients were heavy cigarette smokers, in average 33±8 pack-years. Chest radiographs of these patients were compatible with lung emphysema. Spirometric examinations revealed severe, irreversible pressure-dependent airflow limitations; body plethysmographic measurements revealed overinflation in increased total lung capacities, and transfer factors were greatly reduced. The control group consisted of 14 healthy smokers. Slightly elevated (alpha-1-antitrypsin in our pts., 3.55±0.76 g/L, indicated an acute phase reaction. The highly positive correla­tion was found between Cu and LDH (r=0.81, p<0.001) and between Cu and Mg (r=0.47, p<0.01). These results are correlated to the parameters of acid - base status, and they suggest that it is necessary to determine copper in the blood of patients with COLD in order to correctly evaluate hypoxia.4th Meeting of the Balkan Clinical Laboratory Federation, Budva, Yugoslavi

Ceruloplasmin, copper and zinc in pulmonary emphysemia

We analyzed the blood samples from 20 patients with global respiratory failure (10 males, mean age 56±7 yrs. and 10 females, mean age 60±5 yrs.). All patients were heavy cigarette smokers, in average 33±8 pack-years. Spirometrics examinations suggested severe, irreversible pressure dependent airflow limitations; body plethysmo­graphic measurements revealed overinflalion in increased total lung capacities, and transfer factors were greatly reduced. The control group consisted of 20 healthy smokers. Slightly elevated alfa 1-PI in our patients, 3.55±0.76 g/L, indicated an acute phase reaction. As compared to the control group, we found significantly decreased concentration of zinc (74±24 : 105±34 pg/100 niL, p<0.001). The mean values of ceruloplasmin were similar in the two groups (0.45±0.01 ; 0.37±0.05 g/L). Scrum copper levels were also similar in both groups (126±46 : 134±14pg/100mL). The other authors have stated that in inflam­mation the copper concentration was increased. However our findings could not prove it. Decreased concentration of zinc pointed to the destabilization of lysosomal mem­ branes and increased macrophage activity that liberates proteases.4th Meeting of the Balkan Clinical Laboratory Federation, Budva, Yugoslavi

Activation of Osmium by the Surface Effects of Hydrogenated TiO2 Nanotube Arrays for Enhanced Hydrogen Evolution Reaction Performance

Efficient cathodes for the hydrogen evolution reaction (HER) in acidic water electrolysis rely on the use of expensive platinum group metals (PGMs). However, to achieve economically viable operation, both the content of PGMs must be reduced and their intrinsically strong H adsorption mitigated. Herein, we show that the surface effects of hydrogenated TiO2 nanotube (TNT) arrays can make osmium, a so far less-explored PGM, a highly active HER electrocatalyst. These defect-rich TiO2 nanostructures provide an interactive scaffold for the galvanic deposition of Os particles with modulated adsorption properties. Through systematic investigations, we identify the synthesis conditions (OsCl3 concentration/temperature/reaction time) that yield a progressive improvement in Os deposition rate and mass loading, thereby decreasing the HER overpotential. At the same time, the Os particles deposited by this procedure remain mainly sub-nanometric and entirely cover the inner tube walls. An optimally balanced Os@TNT composite prepared at 3 mM/55 °C/30 min exhibits a record low overpotential (η) of 61 mV at a current density of 100 mA cm−2, a high mass activity of 20.8 A mgOs −1 at 80 mV, and a stable performance in an acidic medium. Density functional theory calculations indicate the existence of strong interactions between the hydrogenated TiO2 surface and small Os clusters, which may weaken the Os−H* binding strength and thus boost the intrinsic HER activity of Os centers. The results presented in this study offer new directions for the fabrication of cost-effective PGM-based catalysts and a better understanding of the synergistic electronic interactions at the PGM|TiO2 interface

TiO2 nanotube arrays decorated with Ir nanoparticles for enhanced hydrogen evolution electrocatalysis

Designing cost-effective hydrogen evolution reaction (HER) electrocatalysts containing highly active, but expensive platinum group metals (PGMs) is key to the commercialization of polymer electrolyte membrane water electrolysis systems for green hydrogen production. Our recent investigations have shown that efficient and durable HER composite cathodes can be prepared by spontaneous deposition of PGM nanoparticles on self-aligned titania nanotube (TNT) arrays formed by anodization [1]. In this synthesis route, anatase TNTs are first cathodically protonated (H-TNT), and then used as the reducing agent for PGM ions at room temperature. Herein, we employ the galvanic displacement strategy to decorate H-TNT arrays with ultrafine Ir nanoparticles [2]. We demonstrate that transforming the top surface morphology of supporting TNT arrays from ordered open-top tubes to bundled nanowires (“nanograss”) is beneficial for exposing more Ir active centers during the HER operation. Consequently, applying very low concentrations of Ir(III) ions in the galvanic displacement step is sufficient to produce exceptionally active nanograss-modified Ir@TNT composites. An optimum Ir@TNT, possessing a low Ir loading of 5.7 μgIr cm–2, requires an overpotential of only –63 mV to reach a current density of –100 mA cm–2 and shows a stable long-term performance in a 1 M HClO4 solution. Computational simulations suggest that the hydrogen-rich TiO2 support not only strongly interacts with anchored Ir particles and weakens their H binding strength to a moderate level, but also actively provides hydrogen for rejuvenation of the Ir active sites at the Ir|H-TiO2 interface, thereby significantly enhancing HER catalysis. [1] U.Č. Lačnjevac, R. Vasilić, T. Tokarski, G. Cios, P. Żabiński, N. Elezović and N. V. Krstajić, Nano Energy 47 (2018) 527. [2] U. Lačnjevac, R. Vasilić, A. Dobrota, S. Đurđić, O. Tomanec, R. Zbořil, S. Mohajernia, N.T. Nguyen, N. Skorodumova, D. Manojlović, N. Elezović, I. Pašti, P. Schmuki, Journal of Materials Chemistry A 8 (2020) 22773

Activation of Osmium by the Surface Effects of Hydrogenated TiO2 Nanotube Arrays for Enhanced Hydrogen Evolution Reaction Performance

Efficient cathodes for the hydrogen evolution reaction (HER) in acidic water electrolysis rely on the use of expensive platinum group metals (PGMs). However, to achieve economically viable operation, both the content of PGMs must be reduced and their intrinsically strong H adsorption mitigated. Herein, we show that the surface effects of hydrogenated TiO2 nanotube (TNT) arrays can make osmium, a so far less-explored PGM, a highly active HER electrocatalyst. These defect-rich TiO2 nanostructures provide an interactive scaffold for the galvanic deposition of Os particles with modulated adsorption properties. Through systematic investigations, we identify the synthesis conditions (OsCl3 concentration/temperature/reaction time) that yield a progressive improvement in Os deposition rate and mass loading, thereby decreasing the HER overpotential. At the same time, the Os particles deposited by this procedure remain mainly sub-nanometric and entirely cover the inner tube walls. An optimally balanced Os@TNT composite prepared at 3 mM/55 °C/30 min exhibits a record low overpotential (η) of 61 mV at a current density of 100 mA cm-2, a high mass activity of 20.8 A mgOs-1 at 80 mV, and a stable performance in an acidic medium. Density functional theory calculations indicate the existence of strong interactions between the hydrogenated TiO2 surface and small Os clusters, which may weaken the Os-H* binding strength and thus boost the intrinsic HER activity of Os centers. The results presented in this study offer new directions for the fabrication of cost-effective PGM-based catalysts and a better understanding of the synergistic electronic interactions at the PGM|TiO2 interface