Effect of Chain Structure on the Various Properties of the Copolymers of Fluorinated Norbornenes with Cyclooctene.

Fluorinated polymers are attractive due to their special thermal, surface, gas separation, and other properties. In this study, new diblock, multiblock, and random copolymers of cyclooctene with two fluorinated norbornenes, 5-perfluorobutyl-2-norbornene and N-pentafluorophenyl-exo-endo-norbornene-5,6-dicarboximide, are synthesized by ring-opening metathesis copolymerization and macromolecular cross-metathesis in the presence of the first- to third-generation Grubbs' Ru-catalysts. Their thermal, surface, bulk, and solution characteristics are investigated and compared using differential scanning calorimetry, water contact angle measurements, gas permeation, and light scattering, respectively.

Olefin-Metathesis-Derived Norbornene-Ethylene-Vinyl Acetate/Vinyl Alcohol Multiblock Copolymers: Impact of the Copolymer Structure on the Gas Permeation Properties.

Commercial metathesis polynorbornene is used for the fabrication of high-damping coatings and bulk materials that dissipate vibration and impact energies. Functionalization of this non-polar polymer can improve its adhesive, gas barrier, and other properties, thereby potentially expanding its application area. With this aim, the post-modification of polynorbornene was carried out by inserting ethylene-vinyl acetate-vinyl alcohol blocks into its backbone via the cross-metathesis of polynorbornene with poly(5-acetoxy-1-octenylene) and subsequent deacetylation and hydrogenation of the obtained multiblock copolymers.

Genetic polymorphisms of reproductive hormones and their receptors in assisted reproduction technology for patients with polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is one of the most common endocrinopathies in women of childbearing, which is defined by the accumulation of multiple, small fluid-filled ovarian cysts without the selection of a single dominant follicle. Most PCOS phenotypes are characterized by the absence of spontaneous ovulation, resistance toward ovulation inductors, the production of a large immature oocytes number, and the high prevalence of ovarian hyperstimulation syndrome, resulting in reduced assisted reproductive technologies (ART) programs effectiveness. The review analyses current data about the relationship between polymorphism genotypes of genes, follicle stimulating hormone (, luteinizing hormone (, anti-Müllerian hormone ( and their receptors genes, gonadotropin-releasing hormone (, estrogen, and progesterone receptors genes, the PCOS risk and the features of ovarian response to stimulation during ART cycles.

Multiblock Copolymers of Norbornene and Cyclododecene: Chain Structure and Properties.

We investigate the structure-property relations of the multiblock copolymers of norbornene with cyclododecene synthesized via the macromolecular cross-metathesis reaction between amorphous polynorbornene and semicrystalline polydodecenamer in the presence of the first-generation Grubbs catalyst. By adjusting the reaction time, catalyst amount, and composition of the initial system, we obtain a set of statistical multiblock copolymers that differ in the composition and average length of norbornene and dodecenylene unit sequences. Structural, thermal, and mechanical characterization of the copolymers with NMR, XRD, DSC (including thermal fractionation by successive self-nucleation and annealing), and rotational rheology allows us to relate the reaction conditions to the average length of crystallizable unit sequences, thicknesses of corresponding lamellas, and temperatures of their melting.

Optimizing Connectivity-Driven Brain Parcellation Using Ensemble Clustering.

This work addresses the problem of constructing a unified, topologically optimal connectivity-based brain atlas. The proposed approach aggregates an ensemble partition from individual parcellations without label agreement, providing a balance between sufficiently flexible individual parcellations and intuitive representation of the average topological structure of the connectome. The methods exploit a previously proposed dense connectivity representation, first performing graph-based hierarchical parcellation of individual brains, and subsequently aggregating the individual parcellations into a consensus parcellation.

Olefin metathesis in multiblock copolymer synthesis.

Multiblock copolymers constitute a basis for an emerging class of nanomaterials that combine various functional properties with durability and enhanced mechanical characteristics. Our mini-review addresses synthetic approaches to the design of multiblock copolymers from unsaturated monomers and polymers using olefin metathesis reactions and other ways of chemical modification across double C=C bonds. The main techniques, actively developed during the last decade and discussed here, are the coupling of end-functionalized blocks, sequential ring-opening metathesis polymerization, and cross metathesis between unsaturated polymers, or macromolecular cross metathesis.

Cross-metathesis of polynorbornene with polyoctenamer: a kinetic study.

The cross-metathesis of polynorbornene and polyoctenamer in d-chloroform mediated by the 1(st) generation Grubbs' catalyst Cl2(PCy3)2Ru=CHPh is studied by monitoring the kinetics of carbene transformation and evolution of the dyad composition of polymer chains with in situ (1)H and ex situ (13)C NMR spectroscopy. The results are interpreted in terms of a simple kinetic two-stage model. At the first stage of the reaction all Ru-benzylidene carbenes are transformed into Ru-polyoctenamers within an hour, while the polymer molar mass is considerably decreased.