PolyHIPEs are porous emulsion-templated polymers synthesized within high internal phase emulsions (HIPEs). HIPEs are highly viscous, paste-like emulsions in which the major, "internal" phase, usually ...defined as constituting more than 74% of the volume, is dispersed as discrete droplets within the continuous, minor, "external" phase. The surge in polyHIPE research and development parallels that of porous polymers in general and reflects the increasing number of potential applications (reaction supports, separation membranes, tissue engineering scaffolds, controlled release matrices, responsive and smart materials, and templates for porous ceramics and porous carbons). This review focuses upon the research and development in polyHIPEs through the prism of the work in our laboratory. The review includes an overview of the developments in polymerization chemistry, in the types of monomers, in the types of stabilization, in the generation of more complex polyHIPE-based systems (e.g. interpenetrating polymer networks, hybrids, bicontinuous polymers), and in unusual materials systems such as waterretaining polyHIPEs and shape-memory polyHIPEs.
The High-Luminosity phase of LHC, scheduled to begin in late 2027, will deliver up to ten times the LHC nominal instantaneous luminosity to the experiments. To ensure sound performance under the ...higher pile-up and radiation conditions, the ATLAS hadronic Tile Calorimeter (TileCal) will replace both the on- and off- detector electronics systems during the LHC long shutdown 3 (2025-2027). The upgraded front-end system will continuously digitize and read out shaped photomultiplier tube (PMT) signals from every TileCal cell at a rate of 40 MHz, transmitting them over high-speed fiber links to the new back-end electronics to be stored in latency pipelines and digitally summed to produce improved trigger tower data for the Level-1 trigger. The front-end electronics are based on radiation-qualified commercial components, and use extensive redundancy to minimize single point failures. The Tile upgrade program has undergone extensive R&D and beam tests, and a “demonstrator” module was installed on ATLAS in 2019 for integration and testing in the actual detector environment.
Objective To determine the contemporary etiology, burden, and short-term outcomes of seizures in neonates monitored with continuous video-electroencephalogram (cEEG). Study design We prospectively ...collected data from 426 consecutive neonates (56% male, 88% term) ≤44 weeks' postmenstrual age with clinically suspected seizures and/or electrographic seizures. Subjects were assessed between January 2013 and April 2015 at 7 US tertiary care pediatric centers following the guidelines of the American Clinical Neurophysiology Society for cEEG for at-risk neonates. Seizure etiology, burden, management, and outcome were determined by chart review by the use of a case report form designed at study onset. Results The most common seizure etiologies were hypoxic-ischemic encephalopathy (38%), ischemic stroke (18%), and intracranial hemorrhage (11%). Seizure burden was high, with 59% having ≥7 electrographic seizures and 16% having status epilepticus; 52% received ≥2 antiseizure medications. During the neonatal admission, 17% died; 49% of survivors had abnormal neurologic examination at hospital discharge. In an adjusted analysis, high seizure burden was a significant risk factor for mortality, length of hospital stay, and abnormal neurological examination at discharge. Conclusions In this large contemporary profile of consecutively enrolled newborns with seizures treated at centers that use cEEG per the guidelines of the American Clinical Neurophysiology Society, about one-half had high seizure burden, received ≥2 antiseizure medications, and/or died or had abnormal examination at discharge. Greater seizure burden was associated with increased morbidity and mortality. These findings underscore the importance of accurate determination of neonatal seizure frequency and etiology and a potential for improved outcome if seizure burden is reduced.
Porous polymers with well-defined porosities and high specific surface areas in the form of monoliths, films, and beads are being used in a wide range of applications (reaction supports, separation ...membranes, tissue engineering scaffolds, controlled release matrices, responsive and smart materials) and are being used as templates for porous ceramics and porous carbons. The surge in the research and development of porous polymer systems is a rather recent phenomenon. PolyHIPEs are porous emulsion-templated polymers synthesized within high internal phase emulsions (HIPEs). HIPEs are highly viscous, paste-like emulsions in which the major, “internal” phase, usually defined as constituting more than 74% of the volume, is dispersed within the continuous, minor, “external” phase. This review focuses upon the recent advances in polyHIPEs involving innovations in polymer chemistry, macromolecular structure, multiphase architecture, surface functionalization, and nanoparticle stabilization. The effects of these innovations upon the natures of the resulting polyHIPE-based materials (including bicontinuous polymers, nanocomposites, hybrids, porous ceramics, and porous carbons) and upon the applications involving polyHIPEs are discussed. The advances in polyHIPEs described in this review are now being used to generate new families of porous materials with novel porous architectures and unique properties.
A typical description of interpenetrating polymer networks (IPN) can be surprisingly simple, systems that consist of two crosslinked polymer networks that are physically entangled but not chemically ...linked. That simplistic description, however, successfully encompasses a wide range of synthesis processes and macromolecular architectures that can include “semi-IPN” (IPN-like systems containing only one crosslinked polymer) and interconnected polymer networks (IPN-like systems that also include a limited amount of inter-network chemical links). The macromolecular topologies of these systems combine kinetically entrapped molecular-level mixing with limited phase separation into a continuous range of nanodomain compositions. This perspective-review presents the family of IPN systems, describes the synthesis parameters used to generate a variety of macromolecular topologies, and discusses the damping properties, the ability to process latex IPN, the mechanical robustness of double network hydrogels, and IPN as templates for porous polymers, as well as recent innovations and cutting-edge applications. The wide gamut of macromolecular topological options described herein will serve as a guide to realizing synergistic behaviors by combining polymers in IPN-like structures.
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•IPN macromolecular topology: two interpenetrating, but not linked, polymer networks.•IPN: entrapped molecular mixing + nanodomains with a continuous range of compositions.•IPN, semi-IPN, latex IPN, interconnected and double networks, IPN-templated porosity.•LIPN processability: phase-separated, strength-forming interparticle nanodomains.•Tuning: sequence, reaction, crosslinking, compatibility, composition, hydrophilicity.
Neonatal seizures Silverstein, Faye S.; Jensen, Frances E.
Annals of neurology,
August 2007, Letnik:
62, Številka:
2
Journal Article
Recenzirano
Odprti dostop
In childhood, the risk for seizures is greatest in the neonatal period. Currently used therapies have limited efficacy. Although the treatment of neonatal seizures has not significantly changed in ...the past several decades, there has been substantial progress in understanding developmental mechanisms that influence seizure generation and responsiveness to anticonvulsants. This review includes an overview of current approaches to the diagnosis and treatment of neonatal seizures, identifies some of the critical factors that have limited progress, and highlights recent insights about the pathophysiology of neonatal seizures that may provide the foundation for better treatment. Ann Neurol 2007
Double-network (DN) hydrogels are a combination of two very different polymer networks. Here, porous hydrogels with DN structures were successfully synthesized in two sequential free-radical ...polymerization steps. The first network was templated within a high internal phase emulsion (HIPE) to yield a hydrogel polyHIPE (HG-PH). The double network hydrogel polyHIPEs (DN-PHs) combined a more rigid highly crosslinked, polyelectrolyte (poly(2-acrylamido-2-methylpropanesulfonic acid), PAMPS) first network with a more ductile, crosslinked, neutral (polyacrylamide, PAAm) second network. The DN-PHs were generated from the as-synthesized HG-PHs by imbibing an aqueous AAm solution followed by polymerization. HG-PHs with 70% porosity absorbed significantly more of the AAm solution than HG-PHs with 85% porosity. The density of the DN-PHs increased with increasing AAm concentration, resulting in an increase in the modulus and toughness of both the swollen and the dry DN-PHs. The DN-PHs based on a HG-PH with 85% porosity did not release their water and did not fail up to compressive strains of 70%, recovering their shapes upon the removal of stress. A comparison with inverse DN-PHs, synthesized using the reverse sequence of polymerization, demonstrated that the properties were strongly dependent both on the composition and on the sequence.
Robust, high-porosity, emulsion-templated double-network hydrogels: the polymerization sequence and the polyelectrolyte and neutral-polymer contents determine the structures and the properties.
A broad neuron-centric conception of contextual modulation is reviewed and re-assessed in the light of recent neurobiological studies of amplification, suppression, and synchronization. Behavioural ...and computational studies of perceptual and higher cognitive functions that depend on these processes are outlined, and evidence that those functions and their neuronal mechanisms are impaired in schizophrenia is summarized. Finally, we compare and assess the long-term biological functions of contextual modulation at the level of computational theory as formalized by the theories of coherent infomax and free energy reduction. We conclude that those theories, together with the many empirical findings reviewed, show how contextual modulation at the neuronal level enables the cortex to flexibly adapt the use of its knowledge to current circumstances by amplifying and grouping relevant activities and by suppressing irrelevant activities.
Emulsion-templated porous polymers (polyHIPEs) with highly interconnected voids that range from a few micrometers to hundreds of micrometers are typically synthesized within the external phases of ...high internal phase emulsions (HIPEs), emulsions containing more than 74% internal phase. Recent advances in emulsion-templated polymers include new developments in HIPE formation, polymerization chemistries, macromolecular structures, crosslinking strategies, porous architectures, and surface functionalization. This article focuses upon emulsion-templated polymers through the prism of the research and development work in our laboratory. The innovative emulsion-templated systems described include shape-memory polymers, encapsulation systems, hydrogels, and porous carbons. This article also briefly reviews recent work in the field and draws some conclusions regarding trends and future directions. The abundance of diverse and disparate research directions pursued under the banner of “emulsion templating” is indicative of its high degree of versatility. Novel families of porous polymers with unique properties can now be devised and designed through the advances described herein.
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•Emulsion templating: innovative porous polymers and encapsulating polymers.•Shape memory foams from a crystallizable polyacrylate: uncoated and hydrogel-coated.•Encapsulation: aqueous solutions, inorganic melts, organic liquids.•Hydrogels: pH and/or temperature responsive, superabsorbents, contaminant adsorbents.•Carbons: hierarchical porosity, nitrogen-doping, hydrothermal carbonization.
Emulsion templating presently extends far beyond the original hydrophobic porous polymers that were synthesized within surfactant-stabilized water-in-oil high internal phase emulsions (HIPEs) by ...using free radical polymerization. This Perspective presents the extraordinary versatility of emulsion templating that has emerged with the growing numbers of HIPE systems, HIPE stabilization strategies, monomers, polymerization chemistries, multicomponent materials, and surface functionalities. Emulsion templating now goes far beyond “porous polymers” by encompassing the encapsulation of aqueous solutions, ionic melts, and organic liquids as well as by encompassing porous carbons and porous inorganics. Herein, we present comprehensive pictures of the state-of-the-art, of the prospective large-scale and niche applications, of the advantages and challenges for industrial scale-up, and of the crucial directions that should be pursued in future work. We demonstrate that it is emulsion templating’s considerable and versatile parameter space that offers opportunities for pioneering work, breakthrough innovations, scientific/engineering achievements, and industrial adoption.
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