Adhesion improvement of polyester/aluminium interface by plasma polymerization pretreatments

Plasma polymerizations (PP) of acrylic acid (AA) and methacrylic acid (MAA) on polyester were used to improve the adhesion of the polyester/aluminium interface. It was found that this adhesion measured by the peel test method is 5-10 times higher than in the case of untreated polyester. Comparisons of the X-ray photoelectron spectroscopy (XPS) results obtained from the treated polyester, the untreated polyester and the reference spectra of poly(acrylic acid) cast from H₂O suggest that the observed adhesion improvement can be explained in terms of the formation of new functionalities at the polyester surface.     

Membrane Trafficking in the Yeast Saccharomyces cerevisiae Model

The yeast Saccharomyces cerevisiae is one of the best characterized eukaryotic models. The secretory pathway was the first trafficking pathway clearly understood mainly thanks to the work done in the laboratory of Randy Schekman in the 1980s. They have isolated yeast sec mutants unable to secrete an extracellular enzyme and these SEC genes were identified as encoding key effectors of the secretory machinery. For this work, the 2013 Nobel Prize in Physiology and Medicine has been awarded to Randy Schekman; the prize is shared with James Rothman and Thomas Südhof. Here, we present the different trafficking pathways of yeast S. cerevisiae. At the Golgi apparatus newly synthesized proteins are sorted between those transported to the plasma membrane (PM), or the external medium, via the exocytosis or secretory pathway (SEC), and those targeted to the vacuole either through endosomes (vacuolar protein sorting or VPS pathway) or directly (alkaline phosphatase or ALP pathway). Plasma membrane proteins can be internalized by endocytosis (END) and transported to endosomes where they are sorted between those targeted for vacuolar degradation and those redirected to the Golgi (recycling or RCY pathway). Studies in yeast S. cerevisiae allowed the identification of most of the known effectors, protein complexes, and trafficking pathways in eukaryotic cells, and most of them are conserved among eukaryotes.     

Method of determination of transient and steady-state conductivity in polyethylene terephthalate ultrathin films

The determination of transient and/or steady-state conductivity of polyethylene terephthalate (PET) ultrathin films by means of electrode configurations involving any load or stress imposed on the measuring area during measurement usually leads to anomalous behaviours of the charging current and thus prevents a good evaluation of the electrical properties of the samples. This can be avoided by the use of a two-electrode system with lateral contacts, to obtain reproducible results without any requirement for previous mechanical, thermal, or electrical treatments (as is often recommended in the literature), and that permits the characterization of industrial films down to 1.5-μm thick in true storage conditions after production. © 1993 John Wiley & Sons, Inc.     

Avidity of IgG antibodies distinguishes primary from non-primary cytomegalovirus infection in pregnant women

OBJECTIVE: To define the epidemiology, risk factors, and unadjusted cost of hemorrhages related to cardiothoracic operations. STUDY DESIGN: We conducted two case-control studies to evaluate the risk of hemorrhage following cardiothoracic operations. The definition of hemorrhage required one of the following: reoperation for bleeding, postoperative loss of greater than 800 mL of blood over 4 hours, or surgeon-diagnosed excessive intraoperative bleeding. SETTING: The cardiothoracic surgery service of a university hospital. RESULTS: Of 511 patients undergoing cardiothoracic operations, 93 (18%) met the definition of hemorrhage. In the first case-control study, 3 (14%) of 21 cases and 0 of 42 controls died (odds ratio [OR], 15.0; 95% confidence interval [CI95], 1.18-191.55). Compared with controls, cases received significantly more packed red blood cells intraoperatively (OR, 1.18/100 mL; CI95, 1.01-1.38), and significantly more platelets (OR, 3.26/100 mL; CI95, 1.47-7.26) and fresh frozen plasma (OR, 1.73/100 mL; CI95, 1.05-.84) in the intensive-care unit. Cases were more likely than controls to receive protamine postoperatively (OR, 3.74; CI95, 1.27-11.02). Previous sternotomy, preoperative aspirin or heparin, and preoperative laboratory values did not predict bleeding. The median unadjusted hospital cost was $3,458 higher for patients who suffered hemorrhage than for controls. To decrease costs, hetastarch (acquisition cost $45/500 mL) was substituted for albumin (acquisition cost $76/100 mL) in the pump priming solution (estimated possible cost savings, $7,000-$53,000/year). Because hemorrhage rates increased subsequently, we conducted a second case-control study that identified patient age (P=.02) and use of greater than 5 mL/kg of hetastarch (OR, 1.82) as risk factors for hemorrhage. The cost of treating hemorrhages exceeded all estimates of possible cost savings ($7,000-$53,000 per year). CONCLUSIONS: Our definition of hemorrhage identified patients who required increased volumes of blood products and who had an increased crude mortality rate and a higher unadjusted cost of hospitalization. Patient age and hetastarch use were risk factors for hemorrhage. Efforts to save money by substituting less expensive products inadvertently may increase costs by increasing the probability of perioperative adverse events.     

Surface analyses of corona-treated poly(ethylene terephthalate)

Poly(ethylene terephthalate) (PET) Mylar® samples were treated by corona discharge in order to improve their adhesive properties. The corona treatments were performed in different atmospheres including nitrogen, ammonia and air. X-ray photoelectron spectroscopy (XPS) was used to investigate the chemical modifications induced at the PET surface by these corona treatments. XPS results show that nitrogen incorporation takes place in the form of non-oxygenated nitrogen functionalities, like amine or cyano groups. These are present at the surface of all the corona-treated samples but in different concentrations depending on the gases used in the corona discharge. Furthermore, XPS analyses performed after heating of the treated samples show a higher thermal stability of the corona-induced surface modifications in the case of nitrogen and ammonia. Ion scattering spectroscopy (ISS) and static secondary ion mass spectroscopy (SIMS) analyses were also performed because of their higher surface sensitivity compared with XPS: ISS reveals that nitrogen is not present at the topmost surface layer of the treated samples but is incorporated just beneath. The outermost surface layer presents a composition rich in oxygen. Finally, static SIMS spectra show that corona treatment induces more surface degradation when performed in air compared with nitrogen or ammonia. These results are discussed in relation to adhesive properties of PET.