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  1. Abstract Background

    Fetal alcohol syndrome (FAS) due to gestational alcohol exposure represents one of the most common causes of nonheritable lifelong disability worldwide. In vitro and in vivo models have successfully recapitulated multiple facets of the disorder, including morphological and behavioral deficits, but far less is understood regarding the molecular and genetic mechanisms underlying FAS.


    In this study, we utilized an in vitro human pluripotent stem cell‐based (hPSC) model of corticogenesis to probe the effects of early, chronic intermittent alcohol exposure on the transcriptome of first trimester‐equivalent cortical neurons.


    We used RNA sequencing of developing hPSC‐derived neurons treated for 50 days with 50 mM ethanol and identified a relatively small number of biological pathways significantly altered by alcohol exposure. These included cell‐type specification, axon guidance, synaptic function, and regional patterning, with a notable upregulation of WNT signaling‐associated transcripts observed in alcohol‐exposed cultures relative to alcohol‐naïve controls. Importantly, this effect paralleled a shift in gene expression of transcripts associated with regional patterning, such that caudal forebrain‐related transcripts were upregulated at the expense of more anterior ones. Results from H9 embryonic stem cells were largely replicated in an induced pluripotent stem cell line (IMR90‐4), indicating that these patterning alterations are not cell line‐specific.


    We foundmore »that a major effect of chronic intermittent alcohol on the developing cerebral cortex is an overall imbalance in regionalization, with enrichment of gene expression related to the production of posterodorsal progenitors and a diminution of anteroventral progenitors. This finding parallels behavioral and morphological phenotypes observed in animal models of high‐dose prenatal alcohol exposure, as well as patients with FAS.

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  2. Abstract

    A non‐volatile conjugated polymer‐based electrochemical memristor (cPECM), derived from sodium 4‐[(2,3‐dihydrothieno[3,4‐b][1,4]dioxin‐2‐yl)methoxy]butane‐2‐sulfonate (S‐EDOT), is fabricated through roll‐to‐roll printing and exhibited neuromorphic properties. The 3‐terminal device employed a “read” channel where conductivity of the water‐soluble, self‐doped S‐PEDOT is equated to synaptic weight and was electrically decoupled from the programming electrode. For the model system, a +2500 mV programming pulse of 100 ms duration resulted in a 0.136 μS resolution in conductivity change, giving over 1000 distinct conductivity states for one cycle. The minimum programming power requirements of the cPECM was 0.31 pJ mm−2and with advanced printing techniques, a 0.1 fJ requirement for a 20 μm device is achievable. The mathematical operations of addition, subtraction, multiplication, and division are demonstrated with a single cPECM, as well as the logic gates AND, OR, NAND, and NOR. This demonstration of a printed cPECM is the first step toward the implementation of a mass produced electrochemical memristor that combines information storage and processing and may allow for the realization of printable artificial neural networks.

  3. Abstract

    Polyphosphonates, a class of polymers with the generic formula –[P(R)(X)–OR'O]n–, exhibit a high degree of modularity due to the range of R, R', and X groups that can be incorporated. As such, these polymers may be designed with a polyethylene oxide (PEO) backbone (R' group) and employed as solid polymer electrolytes (SPEs). Two PEO‐containing polyphosphonate analogs (R = Ph; X = S or Se) were doped with LiPF6and their conductivities were measured. Conductivities were similar (X = S) to or exceeding (X = Se) those of standard PEO systems (just below 10−4S/cm at 100°C). Binding models for Li+were generated using31P{1H}NMR titration experiments. Binding of Li+by these polyphosphonates followed a positive cooperativity model, and varying the X group (S or Se) affected the observed cooperativity (Hill coefficient = 1.73 and 4.16, respectively). The presence of Se also leads to an increase in conductivity as temperature is raised above the Tg, which is likely an effect of reduced Columbic interactions. Because of their modularity and ease with which cation binding can be evaluated using31P{1H} NMR titration experiments, polyphosphonates offer a unique approach for the modification of Li+ion battery technology.

  4. Abstract

    Linear polyphosphonates with the generic formula –[P(Ph)(X)OR′O]n– (X = S or Se) have been synthesized by polycondensations of P(Ph)(NEt2)2and a diol (HOR′OH = 1,4‐cyclohexanedimethanol, 1,4‐benzenedimethanol, tetraethylene glycol, or 1,12‐dodecanediol) followed by reaction with a chalcogen. Random copolymers have been synthesized by polycondensations of P(Ph)(NEt2)2and mixture of two of the diols in a 2:1:1 mol ratio followed by reaction with a chalcogen. Block copolymers with the generic formula –[P(Ph)(X)OR′O](x + 2)–[P(Ph)(X)OR′O](x + 3)– (X = S or Se) have been synthesized by the polycondensations of Et2N[P(Ph)(X)OR′O](x + 2)P(Ph)NEt2oligomers with HOR′O[P(Ph)(X)OR′O](x + 3)H oligomers followed by reaction with a chalcogen. The Et2N[P(Ph)(X)OR′O](x + 2)P(Ph)NEt2oligomers are prepared by the reaction of an excess of P(Ph)(NEt2)2with a diol while the HOR′O[P(Ph)(X)OR′O](x + 3)H oligomers are prepared by the reaction of P(Ph)(NEt2)2with an excess of the diol. In each case the excess, x is the same and determines the average block sizes. All of the polymers were characterized using1H,13C{1H}, and31P{1H} NMR spectroscopy, TGA, DSC, and SEC.31P{1H} NMR spectroscopy demonstrates that the random and block copolymers have the expected arrangements of monomers and, in the case of block copolymers, verifies the block sizes. All polymers are thermally stable up to ~300°C, and the arrangements of monomers in the copolymers (block vs. random) affect their degradation temperatures andTgprofiles.more »The polymers have weight average MWs of up to 3.8 × 104 Da.

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  5. Abstract

    X‐ray radiation exhibits diminished scattering and a greater penetration depth in tissue relative to the visible spectrum and has spawned new medical imaging techniques that exploit X‐ray luminescence of nanoparticles. The majority of the nanoparticles finding applications in this field incorporate metals with high atomic numbers and pose potential toxicity effects. Here, a general strategy for the preparation of a fully organic X‐ray radioluminescent colloidal platform that can be tailored to emit anywhere in the visible spectrum through a judicious choice in donor/acceptor pairing and multiple sequential Förster resonance energy transfers (FRETs) is presented. This is demonstrated with three different types of ≈100 nm particles that are doped with anthracene as the scintillating molecule to “pump” subsequent FRET dye pairs that result in emissions from ≈400 nm out past 700 nm. The particles can be self‐assembled in crystalline colloidal arrays, and the radioluminescence of the particles can be dynamically tuned by coupling the observed rejection wavelength with the dyes' emission.


    New methacrylate monomers with carbazole moieties as pendant groups were synthesized by multistep syntheses starting from carbazoles with biphenyl substituents in the aromatic ring. The corresponding polymers were prepared using a free‐radical polymerization. The novel polymers containN‐alkylated carbazoles mono‐ or bi‐substituted with biphenyl groups in the aromatic ring.N‐alkyl chains in polymers vary by length and structure. All new polymers were synthesized to evaluate the structural changes in terms of their effect on the energy profile, thermal, dielectric, and photophysical properties when compared to the parent polymer poly(2‐(9H‐carbazol‐9‐yl)ethyl methacrylate). According to the obtained results, these compounds may be well suited for memory resistor devices. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem.2019, 57, 70–76

  7. A new N-alkynylated dithieno[3,2- b :2′,3′- d ]pyrrole (DTP) monomer was synthesized using a Buchwald–Hartwig amination of 3,3′-dibromo-2,2′-bithiophene with pent-4-yn-1-amine. The obtained monomer was investigated for the possibility of a pre-polymerization modification via Huisgen 1,3-dipolar cycloaddition (“click”) reaction with azide-containing organic compounds. The synthesized N-alkynylated DTP monomer is soluble in a number of organic solvents and reacts with organic azides via “click” reactions in mild conditions, achieving high yields. The N-alkynylated DTP monomer and its “click”-modified derivative can be electropolymerized to form polymeric films. Herein, the synthesis and characterization of a “click” modified DTP monomer, its pre-modified derivative, and their corresponding polymers are described. The developed method is a facile route to synthesize a new generation of various N-functionalized DTP homopolymers.
    Free, publicly-accessible full text available October 11, 2023
  8. A series of multi-doped yttrium pyrosilicate (YPS) nanoparticles were synthesized using a high temperature multi-composite reactor, and used to explore the radioluminescent properties that have potential for biological applications. The luminescent activators explored in this work were cerium, terbium, and europium. A series of mono-doped YPS nanoparticles were synthesized that have optical and X-ray luminescent properties that span the entire visible spectrum. Energy transfer experiments were investiagted to increase the photo- and X-ray luminescence of terbium and europium. Cerium was used as a sensitizer for terbium where X-ray luminescence was enhanced. Similar results were also obtained using cerium as a sensitizer and terbium as an energy bridge for europium. By leveraging different energy transfer mechanisms X-ray luminescence can be enhanced for YPS nanoparticles.
  9. null (Ed.)
    As the most likely prospect for the construction of neuromorphic networks, the emulation of synaptic responses with memristors has attracted attention in both the microelectronic industries and the academic environment. To that end, a newly synthesized hybrid conjugated polymer with pendant carbazole rings, that is, poly(4-(6-(9 H -carbazol-9-yl)hexyl)-4 H -dithieno[3,2- b :2′,3′- d ]pyrrole) (pC6DTP), was employed in the fabrication of a two-terminal memristor with a Al/pC6DTP/ITO configuration where the polymer was electrochemically doped. Signature biological synaptic responses to voltage spikes were demonstrated, such as potentiation & depression and spike timing dependent plasticity. The device was able to be programed through a 1 mV pulse, requiring only 100 fJ of energy. The voltage-dependent conductive nature of the polymer was speculated to occur through two synergistic mechanisms, one associated with the conjugation along the backbone of the conjugated polymer and one mechanism associated with the pendant heterocyclic rings.