Dual-functional materials via CCTP and selective orthogonal thiol-Michael addition/epoxide ring opening reactions

Poly(glycidyl methacrylate) (PGMA) has been synthesised by cobalt catalysed chain transfer polymerisation (CCTP) yielding, in one step, polymers with two points for post polymerisation functionalisation; the activated terminal vinyl bond and in chain epoxide groups. Epoxide ring-opening and a combination of thiol-Michael addition and epoxide ring-opening has been used for the post-functionalisation with amines and thiols to prepare a range of functional materials

ICC-dementia (International Centenarian Consortium - dementia): an international consortium to determine the prevalence and incidence of dementia in centenarians across diverse ethnoracial and sociocultural groups.

BACKGROUND: Considerable variability exists in international prevalence and incidence estimates of dementia. The accuracy of estimates of dementia in the oldest-old and the controversial question of whether dementia incidence and prevalence decline at very old age will be crucial for better understanding the dynamics between survival to extreme old age and the occurrence and risk for various types of dementia and comorbidities. International Centenarian Consortium - Dementia (ICC-Dementia) seeks to harmonise centenarian and near-centenarian studies internationally to describe the cognitive and functional profiles of exceptionally old individuals, and ascertain the trajectories of decline and thereby the age-standardised prevalence and incidence of dementia in this population. The primary goal of the ICC-Dementia is to establish a large and thorough heterogeneous sample that has the power to answer epidemiological questions that small, separate studies cannot. A secondary aim is to examine cohort-specific effects and differential survivorship into very old age. We hope to lay the foundation for further investigation into risk and protective factors for dementia and healthy exceptional brain ageing in centenarians across diverse ethnoracial and sociocultural groups. METHODS: Studies focusing on individuals aged ≥95 years (approximately the oldest 1 percentile for men, oldest 5th percentile for women), with a minimum sample of 80 individuals, including assessment of cognition and functional status, are invited to participate. There are currently seventeen member or potential member studies from Asia, Europe, the Americas, and Oceania. Initial attempts at harmonising key variables are in progress. DISCUSSION: General challenges facing large, international consortia like ICC-Dementia include timely and effective communication among member studies, ethical and practical issues relating to human subject studies and data sharing, and the challenges related to data harmonisation. A specific challenge for ICC-Dementia relates to the concept and definition of'abnormal' in this exceptional group of individuals who are rarely free of physical, sensory and/or cognitive impairments

Early galaxy formation and its large-scale effects

Galaxy formation is at the heart of our understanding of cosmic evolution. Although there is a consensus that galaxies emerged from the expanding matter background by gravitational instability of primordial fluctuations, a number of additional physical processes must be understood and implemented in theoretical models before these can be reliably used to interpret observations. In parallel, the astonishing recent progresses made in detecting galaxies that formed only a few hundreds of million years after the Big Bang is pushing the quest for more sophisticated and detailed studies of early structures. In this review, we combine the information gleaned from different theoretical models/studies to build a coherent picture of the Universe in its early stages which includes the physics of galaxy formation along with the impact that early structures had on large-scale processes as cosmic reionization and metal enrichment of the intergalactic medium

Terminal functional glycopolymers via a combination of catalytic chain transfer polymerisation (CCTP) followed by three consecutive click reactions

The combination of catalytic chain transfer polymerisation (CCTP) with both thiol-ene and copper catalysed alkyne azide coupling (CuAAC) click chemistry has been employed to give a new route to functional glycopolymers for applications in bioconjugation and biological targeting. Ring opening of poly(glycidyl methacrylate) with sodium azide and subsequent reaction with alkyne functional carbohydrates, as prepared by Fischer glycosylation, has been exploited. This combination of a range of efficient chemistry gives a route to multi gram quantities of glycopolymers avoiding the need for living radical polymerisation chemistry. © 2012 The Royal Society of Chemistry

Adsorption behaviour of sulfur containing polymers to gold surfaces using QCM-D

We investigate the influences that functional group, polymer molecular weight and polymer molecular architecture have on the adsorption behaviour of some sulfur containing oligo(ethylene glycol) polymers to gold. QCM-D and XPS was used in this investigation revealing that disulfide functional groups bind with more mass deposited than dithio, trithio or thiols. This was observed with small di(ethylene glycol) polymers and with higher mass polymers. The effect of the sulfo-groups was not as apparent with higher mass polymers. Longer PEG pendent chains resulted in lower binding overall on the gold surface in comparison to shorter DEG chains caused by shielding of sulfur by the longer pendent chains. Thiols undergo two steps during the adsorption process while all other sulfur species adsorb in one step. XPS revealed the dissociation of disulfide bonds when binding to gold. These findings are important when forming stable polymer films on gold efficiently, with uses in applications from bio-fouling to polymer-lipid bilayers

Controlled Alternate Layer-by-Layer Assembly of Lectins and Glycopolymers Using QCM-D

Layer-by-layer (LBL) assembly of concanavalin A (Con A), peanut agglutinin (PNA) plant lectins, and well-defined synthetic glycopolymers via their biological affinities have been prepared using a quartz crystal microbalance with dissipation monitoring (QCM-D). We demonstrate the use of mannose/galactose glycopolymers as lectin binders due to their selective binding to Con A/PNA, respectively. A detailed analysis of the adsorption processes and the adsorbed layer are provided and tuning the composition of multilayers using a series of well-defined glycopolymers differing only in the pendant sugar ratio is discussed

An investigation into thiol–ene surface chemistry of poly(ethylene glycol) acrylates, methacrylates and CCTP polymers via quartz crystal microbalance with dissipation monitoring (QCM-D)

Thiol-ene reactions at surfaces have been investigated, comparing poly(ethylene glycol) (PEG) acrylate and methacrylate monomers with polymers made by cobalt catalysed chain transfer polymerisation (CCTP) using QCM-D. Thiolated surfaces were generated on silicon dioxide QCM-D sensors, with PEG monomers and polymers subsequently passed over the thiolated surface to study the thiol-ene reaction in the absence and presence of tris(2-carboxyethyl) phosphine, TCEP as catalyst