An improved synthetic method has been developed for oligomeric aromatic ether ketone‐based phthalonitrile (PN) resins. A new curing additive was studied that lowers the cure temperature of the PN resin to around 150 °C and compared to the traditional high‐temperature aromatic diamine. Mechanical and thermo‐oxidative analyses of polymeric samples from both systems were determined and compared under various curing conditions. The PN polymer exhibited low water absorption regardless of the chosen cure system. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1662–1668

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A versatile synthetic method has been developed for oligomeric aliphatic–aromatic ether containing phthalonitrile (PN) resins and applied to the preparation of three unique resin systems. The oligomeric PN monomers were prepared from the reaction of an excess amount of bisphenol A with a dihalo‐aliphatic containing compound in the presence of K2CO3 in dimethylsulfoxide, followed by end‐capping with 4‐nitrophthalonitrile in a two‐step, one‐pot reaction. These PN resin systems exhibited excellent viscosities for molding various shaped articles after thermal curing to yield crosslinked polymers. These polymers offered more mechanical flexibility, when compared with an all aromatic backbone, while still maintaining good thermal stability, dielectric properties, and low water absorption. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 2186–2191

The renewable triphenols, resveratrol and dihydroresveratrol, were used in the preparation of two new phthalonitrile resins (PN), each containing three phthalonitrile groups. These are the first reported PN resins generated from a renewable feedstock. These amorphous PN resins were characterized thoroughly by DSC, NMR spectroscopy and rheometry. The monomers exhibited excellent rheometric viscosities suitable for resin transfer molding and resin infusion molding. After complete cure, the PN polymers exhibited thermal stability to above 500 8C and no glass transition temperature (T g ). As a result of the highly cross-linked nature of the network, these materials exhibited a low water uptake of 1 AE 0.2 % and dielectric constant values of approximately 3.0. These results suggest that resveratrol-derived PN resins are excellent candidates for use in maritime environments and aerospace applications.[a] Dr.

Two new oligomeric sulfone and sulfone-ketone containing phthalonitrile (PN) resins with excellent processability have been developed. The PN monomers were prepared from the reaction of an excess amount of bisphenol S with 4-(chlorophenyl)sulfone or 4,4-dichlorobenzophenone in the presence of a base in a solvent mixture (dimethylsulfoxide/toluene), followed by end-capping with 4-nitro-PN in a two-step, one-pot reaction. These PN resins exhibited good viscosities and cure times for molding into various shapes. After being thermally cured to yield crosslinked polymers, these polymers demonstrated superb mechanical properties, thermo-oxidative stability, and maintained good dielectric properties. Published 2016.† J. Polym. Sci., Part A:Polym.

Alzheimer's disease (AD) has several hallmark features including amyloid-β plaque deposits and neuronal loss. Here, we characterized amyloid-β plaque aggregation and parvalbumin-positive (PV) GABAergic neurons in 6 -9 month old 5xFAD mice harboring mutations associated with familial AD. We used immunofluorescent staining to compare three regions in the frontal cortexprelimbic (PrL), cingulate (Cg, including Cg1 and Cg2) and secondary motor (M2) corticesalong with primary somatosensory (S1) cortex. We quantified the density of amyloid-β plaques, which showed significant laminar and regional vulnerability. There were more plaques of larger sizes in deep layers compared to superficial layers. Total plaque burden was higher in frontal regions compared to S1. We also found layer-and region-specific differences across genotype in the density of PV interneurons. PV neuron density was lower in 5xFAD mice than wild-type, particularly in deep layers of frontal regions, with Cg (−50%) and M2 (−39%) exhibiting the largest reduction. Using in vivo two-photon imaging, we longitudinally visualized the loss of frontal cortical PV neurons across four weeks in the AD mouse model. Overall, these results provide information about amyloid-β deposits and PV neuron density in a widely used mouse model for AD, implicating deep layers of frontal cortical regions as being especially vulnerable.

A method to improve the mechanical properties of phthalonitrile (PN) resins at lower postcure temperatures is achieved by blending a second‐generation oligomeric aromatic ether ketone‐based PN resin with 1,1,1‐tris‐[4‐(3,4‐dicyanophenoxy)phenyl]ethane in varying concentrations. Most of the mixtures exhibit a single softening temperature indicating that the two resins are miscibile in one another at the respective concentrations. After various blends are thermally cured to several postcure temperatures yielding crosslinked polymers, the polymers demonstrate superb mechanical properties and thermooxidative stability at lower overall postcure temperatures.

With an incidence of ~1 in 800 births, Down syndrome (DS) is the most common chromosomal condition linked to intellectual disability worldwide. While the genetic basis of DS has been identified as a triplication of chromosome 21 (HSA21), the genes encoded from HSA21 that directly contribute to cognitive deficits remain incompletely understood. Here, we found that the HSA21-encoded chromatin effector, BRWD1, was upregulated in neurons derived from iPS cells from an individual with Down syndrome and brain of trisomic mice. We showed that selective copy number restoration of Brwd1 in trisomic animals rescued deficits in hippocampal LTP, cognition and gene expression. We demonstrated that Brwd1 tightly binds the BAF chromatin remodeling complex, and that increased Brwd1 expression promotes BAF genomic mistargeting. Importantly, Brwd1 renormalization rescued aberrant BAF localization, along with associated changes in chromatin accessibility and gene expression. These findings establish BRWD1 as a key epigenomic mediator of normal neurodevelopment and an important contributor to DS-related phenotypes.