Cardiac investigations in sudden unexpected death in DEPDC5-related epilepsy

Objective: Germline loss-of-function mutations in DEPDC5, and in its binding partners (NPRL2/3) of the mammalian target of rapamycin (mTOR) repressor GATOR1 complex, cause focal epilepsies and increase the risk of sudden unexpected death in epilepsy (SUDEP). Here, we asked whether DEPDC5 haploinsufficiency predisposes to primary cardiac defects that could contribute to SUDEP and therefore impact the clinical management of patients at high risk of SUDEP. Methods: Clinical cardiac investigations were performed in 16 patients with pathogenic variants in DEPDC5, NPRL2, or NPRL3. Two novel Depdc5 mouse strains, a human HA-tagged Depdc5 strain and a Depdc5 heterozygous knockout with a neuron-specific deletion of the second allele (Depdc5c/−), were generated to investigate the role of Depdc5 in SUDEP and cardiac activity during seizures. Results: Holter, echocardiographic, and electrocardiographic (ECG) examinations provided no evidence for altered clinical cardiac function in the patient cohort, of whom 3 DEPDC5 patients succumbed to SUDEP and 6 had a family history of SUDEP. There was no cardiac injury at autopsy in a postmortem DEPDC5 SUDEP case. The HA-tagged Depdc5 mouse revealed expression of Depdc5 in the brain, heart, and lungs. Simultaneous electroencephalographic–ECG records on Depdc5c/− mice showed that spontaneous epileptic seizures resulting in a SUDEP-like event are not preceded by cardiac arrhythmia. Interpretation: Mouse and human data show neither structural nor functional cardiac damage that might underlie a primary contribution to SUDEP in the spectrum of DEPDC5-related epilepsies. ANN NEUROL 2022;91:101–11

Solvent-free fluidic organic dye lasers

We report on the demonstration of liquid organic dye lasers based on 9-(2-ethylhexyl)carbazole (EHCz), so-called liquid carbazole, doped with green-and red-emitting laser dyes. Both waveguide and Fabry-Perot type microcavity fluidic organic dye lasers were prepared by capillary action under solvent-free conditions. Cascade Forster-type energy transfer processes from liquid carbazole to laser dyes were employed to achieve color-variable amplified spontaneous emission and lasing. Overall, this study provides the first step towards the development of solvent-free fluidic organic semiconducting lasers and demonstrates a new kind of optoelectronic applications for liquid organic semiconductors

Hybrid organic-inorganic liquid bistable memory devices

We demonstrate the realization of the first liquid nonvolatile rewritable memories relying on a blend of liquid carbazole and silver nanoparticles. When an external bias voltage is applied across this single active layer based structure, a bistable current with an ON/OFF ratio of about 2 x 10(2) is observed. Write-read-erase cycles and recorded information stability are also demonstrated. This study provides evidence that hybrid materials hold unexplored promises for original nonvolatile flash memories and should stimulate strong interest in the area of low-cost, large area, flexible data storage devices. (C) 2011 Elsevier B.V. All rights reserved.</p

Thin reduced graphene oxide interlayer with a conjugated block copolymer for high performance non-volatile ferroelectric polymer memory

Polymer ferroelectric-gate field effect transistors (Fe-FETs) employing ferroelectric polymer thin films as gate insulators are highly attractive as a next-generation non-volatile memory. For minimizing gate leakage current of a device which arises from electrically defective ferroelectric polymer layer in particular at low operation voltage, the materials design of interlayers between the ferroelectric insulator and gate electrode is essential. Here, we introduce a new solution-processed interlayer of conductive reduced graphene oxides (rGOs) modified with a conjugated block copolymer, poly(styrene-block- paraphenylene) (PS-b-PPP). A FeFET with a solution-processed p-type oligomeric semiconducting channel and ferroelectric poly(vinylidene fluoride-co- trifluoroethylene) (PVDF-TrFE) insulator exhibited characteristic source-drain current hysteresis arising from ferroelectric polarization switching of a PVDF-TrFE insulator. Our PS-b-PPP modified rGOs (PMrGOs) with conductive moieties embedded in insulating polymer matrix not only significantly reduced the gate leakage current but also efficiently lowered operation voltage of the device. In consequence, the device showed large memory gate voltage window and high ON/OFF source-drain current ratio with excellent data retention and read/write cycle endurance. Furthermore, our PMrGOs interlayers were successfully employed to FeFETs fabricated on mechanically flexible substrates with promising non-volatile memory performance under repetitive bending deformation. © 2014 Elsevier B.V. All rights reserved

Extremely low amplified spontaneous emission threshold and blue electroluminescence from a spin-coated octafluorene neat film

International audienceWe report on the photophysical, amplified spontaneous emission (ASE), and electroluminescence properties of a blue-emitting octafluorene derivative in spin-coated films. The neat film shows an extremely low ASE threshold of 90 nJ/cm2, which is related to its high photoluminescence quantum yield of 87% and its large radiative decay rate of 1.7 × 109 s−1. Low-threshold organic distributed feedback semiconductor lasers and fluorescent organic light-emitting diodes with a maximum external quantum efficiency as high as 4.4% are then demonstrated, providing evidence that this octafluorene derivative is a promising candidate for organic laser applications

Organic Monolithic Natural Hyperbolic Material

© 2019 American Chemical Society.Materials with hyperbolic dispersion are the key to a variety of photonic applications involving nanoimaging, hyper-lensing, and spontaneous emission engineering, due to the availability of high k modes. Here we demonstrate that spin-coated polycrystalline organic semiconducting films with a layered molecular packing structure can exhibit a hyperbolic dispersion over a wide spectral range and support the presence of surface excitonic polaritons. This was evidenced from 670 to 920 nm and is related to the negative real part of the dielectric permittivity of the selected quinoidal organic semiconductor. In addition, the accessible high k modes lead to changes in the spontaneous emission decay rate and photoluminescence quantum yield of emitters placed nearby the organic monolithic (composed of only one molecule and not necessitating an alternating multilayer structure) natural hyperbolic material. This study opens a new route toward single-step solution manufacturing of large-area, low-cost, and flexible organic photonic metadevices with hyperbolic dispersion11sciescopu

Non-volatile organic memory with sub-millimetre bending radius

High-performance non-volatile memory that can operate under various mechanical deformations such as bending and folding is in great demand for the future smart wearable and foldable electronics. Here we demonstrate non-volatile solution-processed ferroelectric organic field-effect transistor memories operating in p- and n-type dual mode, with excellent mechanical flexibility. Our devices contain a ferroelectric poly(vinylidene fluoride-co-trifluoroethylene) thin insulator layer and use a quinoidal oligothiophene derivative (QQT(CN)4) as organic semiconductor. Our dual-mode field-effect devices are highly reliable with data retention and endurance of >6,000s and 100 cycles, respectively, even after 1,000 bending cycles at both extreme bending radii as low as 500μm and with sharp folding involving inelastic deformation of the device. Nano-indentation and nano scratch studies are performed to characterize the mechanical properties of organic layers and understand the crucial role played by QQT(CN)4 on the mechanical flexibility of our devices

Thickness dependence of the fluorescence lifetime in films of bisfluorene-cored dendrimers

The effect of film thickness on fluorescence lifetime, quantum yield, and exciton diffusivity is studied in first-generation bisfluorene-cored dendrimers with E-stilbenyl and biphenyl-based dendrons. A decrease of the fluorescence lifetime and quantum yield is observed in films thinner than 50 nm spin-coated on fused silica substrates. The radiative decay of the singlet excited-state and singlet exciton diffusion rates are independent of the film thickness within a 20% uncertainty. The fluorescence lifetime of dendrimers dispersed in an inert host is also independent of film thickness. The nonradiative decay rate increases by a factor of 4 in thin films of dendrimers with first-generation E-stilbenyl dendrons. The same effect is observed on different glass and sapphire substrates, and it is much weaker in the dendrimer with first-generation biphenyl dendrons, which allows us to rule out quenching by substrate. The data can be explained by long-range (dipole−dipole) energy transfer to quenching sites concentrated at the surface of thin films. The results contribute to understanding of the thin film photophysics and will help development of light-emitting devices