The influence of the mould material on the build-up of internal stresses during autoclave cure of carbon fibre composites was investigated using embedded optical fibre Bragg gratings. Unidirectional ...and cross-ply laminates were cured on four flat moulds: aluminium, steel, carbon composite and carbon foam. From the beginning of cure, the fibres were strained by contact with the expanding mould. The strain increased with the mould thermal expansion and autoclave pressure. As a result, large residual strains were found in the longitudinal direction for the samples cured on aluminium or steel moulds, whereas the samples cured on carbon-based moulds exhibited almost no strain after cooling-down.
Efavirenz increases CYP2C19- and CYP3A-mediated omeprazole metabolism. We hypothesized that CYP2C19 and CYP2B6 genetic polymorphisms influence the extent of induction of omeprazole metabolism by ...efavirenz. Healthy subjects (n=57) were administered a single 20 mg oral dose of omeprazole on two occasions: with a single 600 mg efavirenz dose; and after a 17-day treatment with efavirenz (600 mg per day). DNA was genotyped for CYP2C19*2, *3 and *17 alleles and CYP2B6*6, *4 and *9 alleles using Taqman assays. Omeprazole, its enantiomers and metabolites were measured by liquid chromatography/tandem mass spectrometry. Our results showed that efavirenz increased omeprazole clearances in all CYP2C19 genotypes in non-stereoselective manner, but the magnitude of induction was genotype dependent. Metabolic ratios of 5-hydroxylation of omeprazole were reduced in extensive and intermediate metabolizers of CYP2C19 (P<0.05). No significant associations were observed between CYP2B6 genotypes and induction by efavirenz on omeprazole metabolism. Our data indicate how interplays between drug interactions and CYP2C19 genetic variations may influence systemic exposure of CYP2C19 substrates.
When a thermoplastic polyurethane elastomer (TPU) is co-molded with galvanized steel, the subsequent adhesion and its durability are very sensitive to the chemical bonds created at the interface. ...Silane coupling primers are known for enhancing adhesion between inorganic substrates and several polymers and this study addresses their efficiency at the TPU–metal interface. γ-APS aminosilane was deposited with different parameters, including pH and solvents. Several other surface treatments were studied for comparison: degreasing, corona discharge, acidic etching, gas flame, and a zinc phosphate conversion coating. The adhesion was characterized with a single wire pull-out test derived from the microbond test geometry, after different aging conditions. Results confirmed that γ-APS worked as a coupling agent in between TPU and the inorganic substrate, outperforming all other surface treatments tested in term of strength and durability, but the silane required the appropriate deposition parameters to be really efficient.
In parallel, a finite element approach was proposed for the modeling of fiber reinforced thermoplastic elastomer composites accounting for the non-linear viscoelastic material properties and its results compared to an analytical elastic shear-lag interpretation of the single filament pull-out test. The analytic interpretation was found to be sufficiently accurate for stress analysis but not for fracture mechanics. The FEM analysis offered an evaluation of the internal stresses developed within the entire system, which helped the interpretation of results. The model, compared to experimental results, also revealed that it is important to account for internal stresses, mostly for treatments leading to low intrinsic interfacial shear strength values.
The relative contribution of phenotypic measures and CYP2C9‐vitamin K epoxide reductase complex subunit 1 (VKORC1) polymorphisms to warfarin dose requirements at day 14 was determined in 132 ...hospitalized, heavily medicated patients. Phenotypic measures were (1) the urinary losartan metabolic ratio before the first dose of warfarin, (2) the S:R‐warfarin ratio at day 1, and (3) a dose‐adjusted international normalized ratio (INR) at day 4. CYP2C9 and VKORC1 genotypes were determined by gene chip analysis. In multivariate analyses, the dose‐adjusted INR at day 4 explained 31% of variability observed in warfarin doses at day 14, whereas genotypic measures (CYP2C9‐VKORC1) contributed 6.5%. When S:R‐warfarin ratio was used, genotypes contributed more significantly (23.5%). Finally, urinary losartan metabolic ratio was of low predictive value. The best models obtained explained 51% of intersubject variability in warfarin dose requirements. Thus, combination of a phenotypic measure to CYP2C9‐VKORC1 genotypes represents a useful strategy to predict warfarin doses in patients receiving multiple drugs (11±4 drugs/day).
Clinical Pharmacology & Therapeutics (2008); 83, 5, 740–748. doi:10.1038/sj.clpt.6100434
A technique is presented to measure the capillary pressure drop Δ
P
γ
during infiltration of non-crimp fabrics by a liquid matrix. Three types of liquids are used: polyethylene glycol (PEG) dissolved ...in water, a thermoset epoxy resin and a reactive thermoplastic system. Results show that epoxy resin behaves as a non-wetting liquid with a Δ
P
γ
of 14
kPa when injected under constant pressure. The PEG and the thermoplastic system exhibit a wetting behaviour with Δ
P
γ
of −5.4 and −13.8
kPa, respectively. Constant flow rate experiments furthermore indicate that Δ
P
γ
increases with the fluid velocity, closely following the velocity dependence of the dynamic wetting angle. Thus, a thermodynamically wetting resin may well behave as a non-wetting fluid during Liquid Composite Moulding, when viscous forces dominate over capillarity.
Carbon–epoxy prepregs are generally used to form the skins of honeycomb sandwich structures used in aerospace or racing yachts. For some applications, it is desirable to increase the thickness of the ...skins. In order to achieve an ideal core pressure level during cure for maximal skin–core bonding, the issue of air extraction from the honeycomb cells through the skin during processing thus becomes critical, in particular if vacuum only processing is used. In the present work, partially impregnated prepregs, called semipregs, having high initial transverse permeability to air, are combined with traditional prepregs to form a hybrid skin. Results are presented on the pressure change inside the honeycomb cells and the skin permeability to air during cure, as well as on skin–core adhesion. The final sandwich quality is assessed and found to be comparable to that obtained with prepreg skins.
► IV injection of rhIL-2 preserves LV fractional shortening and remodeling after MI. ► rhIL-2 enhances cardiac angiogenesis. ► rhIL-2 helps preserve the integrity and function of myocardium after MI. ...► Proangiogenic effect of rhIL-2 correlated with the infiltration of NK cells.
We previously demonstrated that injection of IL-2-activated natural killer (NK) cells contribute to vascular remodeling via a4b7 integrin and killer cell lectin-like receptor (KLRG) 1 and promote cardiac repair following myocardial infarction (MI). The aim of the present study is to test the hypothesis that injection of recombinant human interleukin (rhIL)-2 improves angiogenesis and preserves heart function after MI. A single IV injection of rhIL-2 two days following MI improved by 27.7% the left ventricular (LV) fractional shortening of immune competent (C57Bl6) mice, but had no effect on cardiac function of immune-deficient (NOD-SCID IL2Rγnull) mice. Immunohistochemical analysis of C57Bl6 cross sections of heart revealed that collagen deposition was reduced by 23.1% and that capillary density was enhanced in the scar area and the border zone of the infarct respectively by 22.4% and 33.6% following rhIL-2 injection. In addition, rhIL-2 enhanced 1.6-fold the invivo endothelial cell proliferation index and 1.8-fold the number of NK cell infiltrating the infarcted heart, but had no effect on the number of cardiac CD4 and CD8 cells. Invitro, rhIL-2 activated NK cells enhanced cardiac endothelial cell proliferation by 17.2%. Here we show that a single IV injection of rhIL-2 positively impacted cardiac function by improving angiogenesis through a process involving NK cells.
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