Characterization of monoclonal antibodies generated against bovine and porcine prostacyclin synthase and quantitation of bovine prostacyclin synthase

Monoclonal antibodies were raised against prostacyclin synthases purified from bovine and porcine aortae, respectively. Two monoclonal antibodies, RS1 and RS2, were purified and characterized. As shown by enzyme activity precipitation and Western blot analysis, in solubilized bovine and porcine aortae microsomes the monoclonal antibodies reacted only with prostacyclin synthase. The monoclonal antibody RS1 cross-reacts with partially purified prostacyclin synthase from human umbilical veins in an ELISA-based assay. None of the antibodies inhibited the enzyme activity. By combination of the monoclonal antibody RS2 with a polyclonal antibody we established an enzyme-linked immunosorbent assay (ELISA) for quantitation of bovine prostacyclin synthase. ELISA data were confirmed by Western blot analysis. Among different bovine tissues, aortae with 1665 +/- 200 ng/mg microsomal protein showed the highest content of PGIS. Significant lower concentrations were observed in tongue, lung, kidney and thymus ranging from 49 +/- 13.4 to 2.7 +/- 0.9 ng/mg protein. The monoclonal antibody RS1 binds to endothelial cells and vascular smooth muscle cells in human liver tissue.     

Amplification of a Y-chromosomal DNA sequence by the polymerase chain reaction for documentation of residual recipient cells in small samples from bone marrow, peripheral blood and cerebrospinal fluid after bone marrow transplantation

The long arm of the human Y-chromosome contains about 800 to 5000 copies of the tandemly repeated DNA sequence DYZ1. A major part of the repeating unit (pHY10) has been cloned and sequenced. Primers were designed to match a part of this repeat sequence for the amplification of a 154 bp fragment spanning the EcoRI restriction site of the unit. Typical dilution experiments showed that this polymerase chain reaction (PCR) method allows the detection of 5 to 10 male cells among 100,000 female cells, or in 500 microL of cerebrospinal fluid containing only one cell per microL. In addition, the quality of the DNA used for the amplification reaction is less critical, thus allowing analysis of long-term stored samples such as bone marrow smears or dried blood stains spotted onto filter paper, which might contain partially degraded DNA. We applied this technique to detect residual host cells in the clinical setting of human sex-mismatched bone marrow transplantation (BMT). Fourteen patients, receiving transplantations because of leukemias could be supervised so far. Throughout the whole period of monitoring (days +14 until +911 post BMT; median: 160 days), residual host cells were detected in all but three patients. Persistence of host cells in the early phase post-BMT was mostly transient and probably due to long-term surviving host T-lymphocytes. Reappearance of host cells several months after BMT is highly suspicious of relapse from the underlying malignancy. Due to its high sensitivity, PCR is a valuable tool in monitoring the switch from recipient to donor cell population.(ABSTRACT TRUNCATED AT 250 WORDS)     

Incorporation of reactive silver‐tricalcium phosphate nanoparticles into polyamide 6 allows preparation of self‐disinfecting fibers

Polymer fibers are used for a wide range of materials in contact with the human body. Since bacterial contamination may cause diseases, it is desirable to provide fibers with antimicrobial properties. This work investigates the ability of silver‐tricalcium phosphate nanoparticles (Ag/TCP) to build a reactive system when incorporated in polyamide fibers. In the presence of bacteria, the TCP carrier particles are biodegraded and trigger the release of silver. For this work, Ag/TCP nanoparticles (1.3 wt% silver) were produced by flame spray synthesis and subsequently processed with polyamide 6 to fibers (125‐μm thick, containing 260 ppm silver) with the aid of extrusion and melt‐spinning for subsequent antibacterial testing. The fibers were contaminated with the clinically relevant strains Escherichia coli or Streptococcus sanguinis, respectively. The reactive fibers demonstrated significantly reduced plate count within 24 h (the number of colony forming units was reduced by 99.999% with E. coli and 99.6% with S. sanguinis compared with pure PA6 reference fibers). These reactive properties of easily integrated antibacterial silver suggest an implementation of intelligent fibers to a wide range of applications. POLYM. ENG. SCI., 2011. © 2010 Society of Plastics Engineers     

The effect of silica nanoparticles and carbon nanotubes on the toughness of a thermosetting epoxy polymer

Silica nanoparticles and multiwalled carbon nanotubes (MWCNTs) have been incorporated into an anhydride‐cured epoxy resin to form “hybrid” nanocomposites. A good dispersion of the silica nanoparticles was found to occur, even at relatively high concentrations of the nanoparticles. However, in contrast, the MWCNTs were not so well dispersed but relatively agglomerated. The glass transition temperature of the epoxy polymer was 145°C and was not significantly affected by the addition of the silica nanoparticles or the MWCNTs. The Young's modulus was increased by the addition of the silica nanoparticles, but the addition of up to 0.18 wt % MWCNTs had no further significant effect. The addition of both MWCNTs and silica nanoparticles led to a significant improvement in the fracture toughness of these polymeric nanocomposites. For example, the fracture toughness was increased from 0.69 MPam^1/2 for the unmodified epoxy polymer to 1.03 MPam^1/2 for the hybrid nanocomposite containing both 0.18 wt % MWCNTs and 6.0 wt % silica nanoparticles; the fracture energy was also increased from 133 to 204 J/m². The mechanisms responsible for the enhancements in the measured toughness were identified by observing the fracture surfaces using field‐emission gun scanning electron microscopy. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

High temperature compressive creep behavior of BaCe0.65Zr0.2Y0.15O3−δ in air and 4% H2/Ar

The proton conductive material BaCe_0.65Zr_0.2Y_0.15O_3−δ has great potential for the separation and purification of hydrogen. However, due to the demanding application conditions regarding both temperature and atmosphere, the elevated temperature structural stability needs to be characterized and warranted. Hence, in this research work, the elevated temperature compressive creep behavior of BaCe_0.65Zr_0.2Y_0.15O_3−δ in the temperature regime of 850°C to 1200°C was studied in both air and 4% H₂/Ar as a function of the applied stress. The results indicate different creep mechanisms depending on atmosphere and temperature range. While dislocation creep was observed in 4% H₂/Ar over the full range, a dislocation creep mechanism was observed in air at temperatures ≤1050°C and a diffusional creep mechanism at temperature ≥1100°C. A detailed microstructural analysis of the post-creep test specimens revealed that the exposure to oxygen leads to localized stoichiometric changes and a decomposition at the surface.     

Toughening structural adhesives via nano- and micro-phase inclusions

It has been clearly demonstrated that the addition of low concentrations of nanosilica particles to a typical rubber-toughened adhesive, based upon a two-part epoxy formulation, leads to very significant increases in the toughness of the adhesive and also to increases in the glass transition temperature and the single-lap shear strength. The nano-SiO 2 particles have an average particle diameter of 20 nm and are very well dispersed in the epoxy adhesive, and only a concentration of about 1% to 8% by mass of such nanoparticles are needed to achieve significant improvements in the mechanical and thermal performance of the rubber-toughened two-part epoxy adhesive.     

The tensile fatigue behaviour of a silica nanoparticle-modified glass fibre reinforced epoxy composite

An anhydride-cured thermosetting epoxy polymer was modified by incorporating 10 wt.% of well-dispersed silica nanoparticles. The stress-controlled tensile fatigue behaviour at a stress ratio of R = 0.1 was investigated for bulk specimens of the neat and the nanoparticle-modified epoxy. The addition of the silica nanoparticles increased the fatigue life by about three to four times. The neat and the nanoparticle-modified epoxy resins were used to fabricate glass fibre reinforced plastic (GFRP) composite laminates by resin infusion under flexible tooling (RIFT) technique. Tensile fatigue tests were performed on these composites, during which the matrix cracking and stiffness degradation was monitored. The fatigue life of the GFRP composite was increased by about three to four times due to the silica nanoparticles. Suppressed matrix cracking and reduced crack propagation rate in the nanoparticle-modified matrix were observed to contribute towards the enhanced fatigue life of the GFRP composite employing silica nanoparticle-modified epoxy matrix.     

Über die Fluvographie als Methode zur Erfassung des Feuchtigkeitsgehaltes der Hornschicht

Fluvography as a Method for the Detection of Humidity of Stratum corneum The heat transport coefficient λ before and after application of wool alcohol ointment for one hour was measured fluvographically on the back of the hand in 15 test subjects. In addition, the tourniquet test was performed to differentiate into λ of the skin with blood flow and λ_G of the skin without blood flow. The results show that the external preparation tested increases the λ_G of the skin without blood flow, but does not influence the microcirculation. In a further 60 test subjects, λ was measured on the back at symmetrical points before and after application of external preparations. The external preparations applied were wool alcohol ointment, aqueous wool alcohol ointment, white vaseline, benzoinated lard, 5% salicylic acid in wool alcohol ointment and 10% precipitated sulfur in wool alcohol ointment. All external preparations tested lead to an increase in λ. However, the increase was most pronounced with wool alcohol ointment. These results may be interpreted in terms on an increase in the water content of the stratum corneum caused by the preparations applied. However, this effect differs in intensity in the different external preparations. The measurement paradigm described may be a suitable method for measuring the water content of the stratum corneum.     

Correlation between domain wall properties and material parameters in amorphous SmCo-films

Amorphous Sm1-xcox-films with uniaxial in-plane anisotropy with various Co-concentrationsx (.67 leq x leq .91)and various film thicknesses d (10nm leq d leq 350nm) have been prepared by flash-evaporation of SmCo-alloy powders. The saturation magnetization decreases linearly with x in the whole concentration range, whereas the coercive field increases linearly with x down toxapprox74and then decreases. Drastic changes in all magnetic properties occur when at a given chemical composition the film thickness is reduced belowdapprox50nm. Head-on domains are separated by zig-zag walls whose amplitudes are analyzed as a function of the material parameters.