Semiconducting to metallic-like boron doping of nanocrystalline diamond films and its effect on osteoblastic cells

The impact of boron doping level of nanocrystalline diamond (NCD) films on the character of cell growth (i.e., adhesion, proliferation and differentiation) is presented. Intrinsic and boron-doped NCD films were grown on Si/SiO₂ substrates by microwave plasma CVD process. The boron-doped samples were grown by adding trimethylboron (TMB) to the gas mixture of methane and hydrogen. Highly resistive (0 ppm), semiconducting (133 or 1000 ppm), and metallic-like (6700 ppm) NCD films were tested as the artificial substrates for the cultivation of osteoblast-like MG 63 cells. The conductivity and surface charge increased monotonically with the increasing boron content. All NCD substrates showed good biocompatibility and stimulated the adhesion and growth of MG 63 cells. Higher osteocalcin concentration (by more than 30%) for the cells growing on 1000 and 6700 ppm boron-doped NCD films was found which indicates an enhancement in the cell growth biochemistry.     

Filler and mobility of rubber matrix molecules

Filler surfaces in elastomers influence mobility of rubber matrix molecules. Mobility of rubber matrix molecules then determines elastomer properties and behaviour of rubber products in applications. Effect of filler in elastomer–filler system is usually characterized by different properties: Modulus seem to depend mainly on filler cluster size and filler network behaviour but effect of mobility of rubber matrix molecules is also evident. Bound rubber characterize fraction of rubber immobilized on filler particle surfaces, however, can be obtained only for uncured rubber–filler compounds. As it is shown in this paper, the permeability coefficient of permanent gas in rubber–filler system could characterize mobility of rubber matrix molecules around the filler particles and the activation energy of its permeation could characterize strength of physical bonds between the rubber matrix molecules and surface of filler particles.     

Expansion of Access Tunnels and Active‐Site Cavities Influence Activity of Haloalkane Dehalogenases in Organic Cosolvents

The use of enzymes for biocatalysis can be significantly enhanced by using organic cosolvents in the reaction mixtures. Selection of the cosolvent type and concentration range for an enzymatic reaction is challenging and requires extensive empirical testing. An understanding of protein–solvent interaction could provide a theoretical framework for rationalising the selection process. Here, the behaviour of three model enzymes (haloalkane dehalogenases) was investigated in the presence of three representative organic cosolvents (acetone, formamide, and isopropanol). Steady‐state kinetics assays, molecular dynamics simulations, and time‐resolved fluorescence spectroscopy were used to elucidate the molecular mechanisms of enzyme–solvent interactions. Cosolvent molecules entered the enzymes' access tunnels and active sites, enlarged their volumes with no change in overall protein structure, but surprisingly did not act as competitive inhibitors. At low concentrations, the cosolvents either enhanced catalysis by lowering K_0.5 and increasing k_cat, or caused enzyme inactivation by promoting substrate inhibition and decreasing k_cat. The induced activation and inhibition of the enzymes correlated with expansion of the active‐site pockets and their occupancy by cosolvent molecules. The study demonstrates that quantitative analysis of the proportions of the access tunnels and active‐sites occupied by organic solvent molecules provides the valuable information for rational selection of appropriate protein–solvent pair and effective cosolvent concentration.     

Thermal and water vapor transmission through porous warp knitted 3D spacer fabrics for car upholstery applications

This paper deals with water vapor transmission and thermal properties of various warp knitted spacer fabrics. In this work, thermal and water vapor permeability of different spacer fabrics have been evaluated by varying the structure, areal density, thickness, type of raw materials, etc. The air permeability and water vapor transmission of the fabrics were measured using the Textest FX-3300 air permeability tester and PERMETEST. The thermal behavior of fabrics was evaluated by Alambeta instrument. Analysis of Variance (ANOVA) was performed using new statistical software in order to compare the influence of different fabric parameters on thermo-physiological behavior of samples. This study established that the raw materials, type of spacer yarn, density, thickness, and tightness of surface layer have significant influence on thermal conductivity in spacer fabrics. The parameters which mainly influence the water vapor permeability of these fabrics are porosity, density, and thickness. The empirical model for thermal conductivity calculation shows very high accuracy when compared with experimental results. The statistical model for spacer fabrics also predicts the thermo-physiological properties with very high accuracy. These findings are important requirements for further designing of spacer fabrics for car seats and back supports.     

Growth and Potential Damage of Human Bone-Derived Cells on Fresh and Aged Fullerene C60 Films

Fullerenes are nanoparticles composed of carbon atoms arranged in a spherical hollow cage-like structure. Numerous studies have evaluated the therapeutic potential of fullerene derivates against oxidative stress-associated conditions, including the prevention or treatment of arthritis. On the other hand, fullerenes are not only able to quench, but also to generate harmful reactive oxygen species. The reactivity of fullerenes may change in time due to the oxidation and polymerization of fullerenes in an air atmosphere. In this study, we therefore tested the dependence between the age of fullerene films (from one week to one year) and the proliferation, viability and metabolic activity of human osteosarcoma cells (lines MG-63 and U-2 OS). We also monitored potential membrane and DNA damage and morphological changes of the cells. After seven days of cultivation, we did not observe any cytotoxic morphological changes, such as enlarged cells or cytosolic vacuole formation. Furthermore, there was no increased level of DNA damage. The increasing age of the fullerene films did not cause enhancement of cytotoxicity. On the contrary, it resulted in an improvement in the properties of these materials, which are more suitable for cell cultivation. Therefore, fullerene films could be considered as a promising material with potential use as a bioactive coating of cell carriers for bone tissue engineering.     

Application of land-use planning criteria for the control of major accident hazards: a case-study

Land-use planning (LUP) with respect to major accident hazards is one of the more important requirements of Directive 96/82/EC (the so-called Seveso II Directive). Different approaches were developed by the Member States of the European Union in order to implement this aspect of the Directive. This study focuses on the comparison of the specific approaches developed for LUP with respect to major accidents hazards. An Italian industrial area has been selected to perform a case study. The different LUP criteria have been used both to evaluate the present state of the area and the effect of several proposed hazard reduction actions. The results obtained have allowed a comparison of the different LUP methodologies. Critical steps in the application of the different LUP criteria have been identified, and the different priorities of hazard reduction actions resulting from risk-based and consequence-based approaches have been highlighted.     

EQUILIBRIUM MOISTURE CONTENT OF DRIED BLOOD FLOUR FN THE TEMPERATURE RANGE OF 20 - 50°C

The paper presents results of water sorption tests of dried blood flour carried out tinder laboratory conditions and mathematical analyses of sorption isotherms obtained. Moisture equilibrium data were investigated at air temperatures in the range of 20-50°C and water activity ranging from 0 4 to 0 99. The experimental procedure used was a gravimetric dynamic method with continuous registration of sample weight changes. Sorption capacity decreases as temperature increases. Rehydration of the dried material results in hysteresis but this phenomenon was small. Four models of equilibrium moisture content/equilibrium relative air humidity (Chung—Pfost. Halsey. Henderson, and Oswin) were evaluated for their ability to fit data for the samples of dried blood. The modified Henderson equation was a good model for moisture adsorption and desorption of dried blood flour     

Thermal Conductivity Measurement of Bulk Solids

The coefficient of thermal conductivity of particulates and powders is of great importance in process engineering. The prediction of thermal properties of powders using empirical equations is still difficult due to the wide range of specific attributes. This article describes a new measurement methodology for a laboratory device that can be used to determine the thermal conductivity of bulk solids. The presented results show that the created device is highly applicable in industrial practice. It is possible to examine the coefficient of thermal conductivity depending on the sample temperature, the granulometry results and the morphological composition, the moisture content, the degree of consolidation, and other variables that may enter into the entire process and affect it significantly.     

Synthesis of poly(sebacic anhydride): effect of various catalysts on structure and thermal properties

Combining different polymeric systems can be a useful tool to create new networks with different characteristics with respect to the starting materials. In this work, hydrogels composed of gellan gum (GG) and polyethylene glycol dimethacrylate (PEG-DMA) were realized to overcome the fragility problems of physical gels of GG, which limit their biological application as scaffold for tissue engineering. The two polymeric systems were combined using different synthetic approaches, with particular attention to the double network strategy (DN). The influence of several parameters on the mechanical properties, such as the time of diffusion and the molecular weight of PEG-DMA, were evaluated by rheological studies and compressive texture analyses. The hydrogels were also investigated for their ability to swell and release model molecules with different sterical hindrances, such as vitamin B12 and myoglobin. Finally, to estimate the biological safety of the hydrogels, their effect on mitochondrial function of human fibroblasts was investigated.