The in-vitro effects of nicotine and cotinine on sperm motility

Swim-up spermatozoa from the seminal samples of non-smokers, usually not exposed to passive smoking, were treated in vitro with nicotine (NIC) and cotinine (COT) at the average levels found in smokers' seminal plasma and at levels 500 times higher than this average. This was done to evaluate the action of these drugs on sperm motility. Each sample was allowed to swim up in Tyrode's solution with or without the drug; the study was carried out at time 0 and +1, +2, +4, +8 and +24 h of incubation, using a light microscope and a CASA system (experiment 1). In addition, the direct action of smoke on spermatozoa was studied using aspirated cigarette smoke (experiment 2). Kinetic parameters were then measured at 30 min, 45 min and 60 min starting from the last smoke injection. The first experiment showed that NIC and COT at average levels did not produce statistically significant variations of the kinetic parameters studied up to 24 h. However, the much higher concentration significantly altered all the kinetic variables in relation to the time of incubation. The second experiment with smoke in toto demonstrated a sharp reduction in all the sperm kinetic parameters. This reduction was seen after 30 min exposure to smoke and increased progressively until almost complete immotility at 1 h of exposure. These results suggest that NIC and COT are not responsible for the harmful effects of cigarette smoke on sperm kinetic parameters reported in the literature.     

Estimating distributed anatomical connectivity using fast marching methods and diffusion tensor imaging

A method is presented for determining paths of anatomical connection between regions of the brain using magnetic resonance diffusion tensor information. Level set theory, applied using fast marching methods, is used to generate three-dimensional time of arrival maps, from which connection paths between brain regions may be identified. The method is demonstrated in the normal brain and it is shown that major white matter tracts may be elucidated and that multiple connections and tract branching are allowed. Maps of connectivity between brain regions are also determined. Four options are described for estimating the degree of connectivity between regions.     

Evolution of the millimeter-wave collective Thomson scattering system of the high-field tokamak Frascati Tokamak Upgrade

We first describe the improved receiving system of the diagnostic experiment of millimeter-wave collective Thomson scattering being run on the Frascati Tokamak Upgrade (FTU), and then discuss some peculiar problems and new operating procedures related to the investigation of strong anomalous spectra of nonthermal origin, many-orders-of-magnitude stronger than the ion thermal feature merged in them, systematically observed in the experimentation, and finally ascribed to a perturbation of the gyrotron that generates the probing beam. Arguments in favor of a more general valence of the solutions actuated for the specific case of FTU are finally given.     

Interfacial properties of regenerated cellulose fiber/polystyrene composite materials. Effect of the coupling agent's structure on the micromechanical behavior

The interfacial properties of polystyrene/regenerate cellulose fiber composite materials are characterized using micromechanical tests such as the single fiber fragmentation and microbond (“microdrop test”). The cellulose fibers were grafted with different copolymers of different chemical structures as well as different molar masses ranging from 300 to 18,000 (ASA, jeffisocyanate, commercial poly)styrene‐co‐maleic anhydride and “home‐made” poly(styrene‐co‐TMI). The two polystyrene based copolymers have been shown to be miscible with polystyrene. It was found that the higher improvement of the interfacial shear strength was obtained when the fiber is grafted with the higher molecular weight, i.e., the poly(styrene‐co‐TMI).     

Modification of cellulose fibers with functionalized silanes: Effect of the fiber treatment on the mechanical performances of cellulose–thermoset composites

Unsaturated polyester and epoxy resin matrices were filled with silane‐treated cellulose fibers and the ensuing composites were tested in terms of mechanical properties before and after accelerated aging consisting of their immersion into water. The coupling agents used were γ‐aminopropyltriethoxysilane (APS), γ‐methacrylopropyltrimethoxysilane (MPS), hexadecytrimethoxysilane, and γ‐mercaptopropyltrimethoxysilane (MRPS) and those containing reactive functions capable of reacting at one end with the fibers and at the other with the matrix, namely, APS, MPS, and MRPS, were more efficient in improving the mechanical properties of the composites. The immersion into water induced a drastic loss of mechanical properties of the materials. The water uptake of the composites was also studied and showed that the silane treatment was poorly efficient in preventing cellulose from water absorption. The fracture surfaces were inspected by scanning electron microscopy, which confirmed the quality of the interface. These observations were in agreement with the results obtained from the dynamic mechanical characterization. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 974–984, 2005     

Polyurethane from kraft lignin

The condensation of lignin with hexamethylene diisocyanate (HDI) or of a mixture of lignin-poly(ethylene oxide) (PEO) with HDI was investigated. The lignin used in this study was a kraft lignin from Pinus maritima, and was obtained from black liquor by acidification, filtration and vacuum drying. Thermogravimetric analysis was carried out to compare the weight loss against temperature of polyurethanes based on kraft lignin and hexamethylene diisocyanate, or of mixed polyurethanes lignin-PEO-HDI, with that of kraft lignin alone. It was shown that lignin can react with isocyanates in rather mild conditions to give polyurethanes, confirming previous results performed with model molecules. Some mechanical properties (Young's modulus and rupture strength) and glass transition temperature were also measured on the various above materials. In all cases it was concluded that lignin participates to the polycondensation reaction. As to rigid foams, it was found that polyurethanes prepared with oxypropylated glycerol, ethylene glycol and kraft lignin, in the weight proportions of 100/30/15, and HDI had good dimensional stability, and thermal and mechanical properties comparable to those of equivalent industrial materials.     

Correlation between ionic conductivity and7Li-NMR of polyether-polyurethane networks containing lithium perchlorate

Summary The effect of temperature on the ionic conductivity and the⁷Li NME line width of a polyether-polyurethane network containing lithium perchlorate was studied. A treatment of the results based on free-volume principles yielded a linear correlation between the logarithm of the reduced conductivity, _T /_{T 0}, and the logarithm of the reduced⁷Li NMR line width, _T/_{T 0}, for a given reference temperature, T_o=323 K.     

Anionic polymerization of butadiene with organosodium soluble catalysts and structure of the resulting polymers

The structure of liquid polybutadienes prepared by anionic catalysts with toluene as transfer agent was studied by ¹³C n.m.r. and information concerning initiation, propagation and transfer mechanism was obtained. A complete characterization of the fractions obtained by high vacuum distillation is also reported.     

Mechanism of high ionic conductivity in elastomeric networks

The viscoelastic properties and the ionic conductivity of polyether-polyurethane networks containing alkali metal salts have been studied at various temperatures, salt concentrations and network structures. The reduced temperature, TT_g, is the predominant parameter which governs the viscoelastic behaviour and the ionic conductivity of these networks. Using the free volume concept an expresssion is derived for the ionic conductivity, irrespective of the macrostructure involved. The logarithm of the reduced conductivity, σ_T/σ_TR (which is the ratio of the conductivity at a given temperature to that at the reference temperature), is a linear function of the shift factor, log a_T, given by the dynamic mechanical properties. A comparison is made between the WLF parameters C₁ and C₂, obtained from conductivity and viscoelastic measurements.     

Urethanes and polyurethanes bearing furan moieties

Summary In view of a study on the preparation and properties of polyurethanes containing furan rings, it was deemed necessary to carry out a preliminary investigation on the synthesis and characterization of simple furanic urethanes given the paucity of information available on this family of compounds. Three types of combinations were tested, viz; (i) furanic alcohols plus non-furanic isocyanates; (ii) non-furanic alcohols plus furanic isocyanates; (iii) furanic alcohols plus furanic isocyanates. The 21 urethanes thus obtained were fully characterized: they are stable (with one exception) and their synthesis is not marred by secondary reactions, ie the furan ring does not introduce side effects.The financial assistance of the Agence Française pour la Maîtrise de l'Energie is gratefully aknowledged.