Gel-like layer development during formation of thin anodic films on titanium in phosphoric acid solutions

Anodising of commercial pure titanium in phosphoric acid solutions at different concentrations (0.5-4 M) have been investigated using galvanostatic and potentiodynamic polarisation techniques. Under galvanostatic conditions at low current densities (0.1-0.6 A m⁻²), the chrono-potentiometric curves always show a linear section in the early stage of the process. The slope of the linear section, dE/dt, decreases initially and then increases with increasing H₃PO₄ concentration, with the minimum slope at a concentration, ∼2 M. Under potentiodynamic conditions at this concentration the samples exhibit a different anodic behaviour. The development of gel-like layer during formation of thin anodic films on titanium in H₃PO₄ solutions is proposed to account for experimental observations.     

Synthesis of novel tricalcium phosphate-bioactive glass composite and functionalization with rhBMP-2

A functionalization is required for calcium phosphate-based bone substitute materials to achieve an entire bone remodeling. In this study it was hypothesized that a tailored composite of tricalcium phosphate and a bioactive glass can be loaded sufficiently with rhBMP-2 for functionalization. A composite of 40 wt% tricalcium phosphate and 60 wt% bioactive glass resulted in two crystalline phases, wollastonite and rhenanite after sintering. SEM analysis of the composite’s surface revealed a spongious bone-like morphology after treatment with different acids. RhBMP-2 was immobilized non-covalently by treating with chrome sulfuric acid (CSA) and 3-aminopropyltriethoxysilane (APS) and covalently by treating with CSA/APS, and additionally with 1,1′-carbonyldiimidazole. It was proved that samples containing non-covalently immobilized rhBMP-2 on the surface exhibit significant biological activity in contrast to the samples with covalently bound protein on the surface. We conclude that a tailored composite of tricalcium phosphate and bioactive glass can be loaded sufficiently with BMP-2.     

3,4-Dehydro-L-proline Induces Programmed Cell Death in the Roots of Brachypodium distachyon

As cell wall proteins, the hydroxyproline-rich glycoproteins (HRGPs) take part in plant growth and various developmental processes. To fulfil their functions, HRGPs, extensins (EXTs) in particular, undergo the hydroxylation of proline by the prolyl-4-hydroxylases. The activity of these enzymes can be inhibited with 3,4-dehydro-L-proline (3,4-DHP), which enables its application to reveal the functions of the HRGPs. Thus, to study the involvement of HRGPs in the development of root hairs and roots, we treated seedlings of Brachypodium distachyon with 250 µM, 500 µM, and 750 µM of 3,4-DHP. The histological observations showed that the root epidermis cells and the cortex cells beneath them ruptured. The immunostaining experiments using the JIM20 antibody, which recognizes the EXT epitopes, demonstrated the higher abundance of this epitope in the control compared to the treated samples. The transmission electron microscopy analyses revealed morphological and ultrastructural features that are typical for the vacuolar-type of cell death. Using the TUNEL test (terminal deoxynucleotidyl transferase dUTP nick end labelling), we showed an increase in the number of nuclei with damaged DNA in the roots that had been treated with 3,4-DHP compared to the control. Finally, an analysis of two metacaspases’ gene activity revealed an increase in their expression in the treated roots. Altogether, our results show that inhibiting the prolyl-4-hydroxylases with 3,4-DHP results in a vacuolar-type of cell death in roots, thereby highlighting the important role of HRGPs in root hair development and root growth.     

Effect of iron enrichment with GIC or FeCl3 on the pore structure and reactivity of coking coal

The effect of a Lewis acid addition to a coking coal on the porosity and reactivity towards steam of the resulting iron enriched coal chars are studied. GIC (FeCl₃ graphite intercalation compound) or free FeCl₃ are used as iron containing additives. Coal iron enrichment was performed using either directly FeCl₃ in vapour phase, or by mixing of coal and additives in decaline or by common grinding of coal and additives under argon. Iron enriched coals were carbonized at 750°C (heating RATE = 5°C min) and activation made with pure steam at 800°C to a burn-off off of 50 wt%. The pore structures of coal chars before and after activation were evaluated on the basis of CO₂ and C₆H₆ sorption at 25°C. A significant development of the microporosity is observed in the iron enriched char before activation and its steam reactivity is also increased. After activation, BET surface area values are increased in presence of iron, and porosity is mainly microporous.     

The application of photointerpretation for recognizing and estimating alluvial soils beds in the area of flysch in the Polish Carpathian Mts.

The very specific structure of mountain river terraces in the area of flysch in the Carpathian Mts. means, that the lowest terraces consist almost entirely of loose rocks (soils), when, at the same time higher terraces have in principle bipartite structure. The upper part of high terraces consists of cohesive soils, whereas the bottom (lower) part includes loose / non cohesive / soils. Taking into consideration this principle, and recognizing and contouring on the aerial photo the appropriate geomorphological form of a lower or higher terrace, the area of the bed can be established. In the paper a scheme is given in which the geomorphological characteristics and properties of beds situated in valleys and on adjacent slopes is given. The beds interpretated during laboratory photo-interpretation were then verified by field photo-interpretation (mapping) as well as with boreholes / in very limited number / in order to obtain the structure and thickness of the bed.     

Yeast flora of non-radurised and radurised minced beef — a taxonomic study

Yeast flora present in minced beef before and after radurisation were examined. No reduction in the number of yeast cells was observed after the meat was radurised at a dose of 2.5 kGy. A definite increase in the number of psychrotrophic yeast was observed in radurised meat after 14 days of storage at 4°C. The recovered yeast flora comprised representatives of the following species: Candida famata (9 isolates); C. lipolytica (4 isolates); C. parapsilosis (20 isolates); C. sake (27 isolates); C. zeylanoides (28 isolates); Cryptococcus albidus var. albidus (6 isolates); Cr. infirmo-miniatus (1 isolate); Cr. laurentii var. laurentii (31 isolates); Trichosporon cutaneum (1 isolate); Tr. pullulans (2 isolates); Rhodotorula minuta var. texensis (1 isolate); Rh. rubra (1 isolate).     

Interactions of single-walled carbon nanotubes with monosaccharides

Closed-end single-walled carbon nanotubes were wetted in aqueous solutions of monosaccharides, forming weak surface complexes, as proven by the estimation of the content of monosaccharides in complexes isolated from aqueous solutions. The complexation was confirmed by micro-Raman spectroscopy. The Gaussian 03 (Molecular Mechanics UFF method) computations of total energy of the single-walled carbon nanotube-monosaccharides inclusion and surface complexes showed that inclusion complexes should be more stable than corresponding surface complexes. Computed total energies for particular complexes pointed to a lack of preferences for the formation of complexes with either alpha- or beta-tautomers and either pyranoses or furanoses. The forms preferred in the formation of the surface complexes usually differ from these favored in the formation of the inclusion complexes.     

An integrated analysis of ergonomics and time consumption in Swedish 'craft-type' car disassembly

Car disassembly is at the edge of extensive rationalization due to increased legislative demands for recycling. This study focused on (1) assessing current mechanical exposures (physical work loads) for comparison with future rationalised systems, with particular emphasis on time aspects, (2) analysing disassembly work in terms of time consumption and exposures in constituent tasks as defined by a loss analysis technique, and (3) predicting the consequences of car disassembly rationalisation for mechanical exposures. The study showed that disassembly implied pronounced circulatory loads, and that more walking and higher lumbar peak loads were found than in studies of assembly work. Value-adding tasks comprised 30% of the total working time, and implied higher postural exposures for the head, arm, trunk and wrist, as well as less opportunities to recover, as compared to non-value-adding tasks. Organisational-type rationalization can be expected to increase the time spent in value-adding work, thus increasing local exposures for the average worker, while a concurrent increase in mechanization level might reduce circulatory exposures, the amount of walking, and peak lumbar loads.