Comparison of Pantoprazole Concentrations in Simultaneous Cerebrospinal Fluid and Serum Samples.

BACKGROUND: Pantoprazole is a proton pump inhibitor drug mainly used for treating peptic diseases. Adverse effects of pantoprazole in the occasional central nervous system (CNS) include headache, vertigo and sleep disturbances. Data in rats suggest that proton pumps are expressed in the inner ear and in the epithelium of the choroid plexus, which would be a potential target to mediate such proton pump inhibitor effects. METHODS: To assess the distribution of pantoprazole into the human CNS despite its low lipophilicity (log p = 0.5), we quantified pantoprazole concentrations by liquid chromatography/tandem mass spectrometry in serum and cerebrospinal fluid retain samples withdrawn simultaneously. Twenty-six sample pairs were obtained from 23 neurological patients with therapeutic administration of pantoprazole prior to sampling. RESULTS: Median (interquartile range) serum concentration of total pantoprazole was 142 ng/ml (30.8-622). Cerebrospinal fluid concentration of total pantoprazole was 2.79 ng/ml (1.59-7.3) and reached 2.0% (1.0-4.5%) of simultaneous serum concentrations. CONCLUSION: This value corresponds to the unbound fraction of pantoprazole in serum reported previously and indicates that pantoprazole CNS concentrations are high enough to exert some effects on possible CNS targets.

Atmospheric influence upon crystallization and electronic disorder and its impact on the photophysical properties of organic-inorganic perovskite solar cells.

Recently, solution-processable organic-inorganic metal halide perovskites have come to the fore as a result of their high power-conversion efficiencies (PCE) in photovoltaics, exceeding 17%. To attain reproducibility in the performance, one of the critical factors is the processing conditions of the perovskite film, which directly influences the photophysical properties and hence the device performance. Here we study the effect of annealing parameters on the crystal structure of the perovskite films and correlate these changes with its photophysical properties. We find that the crystal formation is kinetically driven by the annealing atmosphere, time and temperature. Annealing in air produces an improved crystallinity and large grain domains as compared to nitrogen. Lower photoluminescence quantum efficiency (PLQE) and shorter photoluminescence (PL) lifetimes are observed for nitrogen annealed perovskite films as compared to the air-annealed counterparts. We note that the limiting nonradiative pathways (i.e., maximizing PLQE) is important for obtaining the highest device efficiency. This indicates a critical impact of the atmosphere upon crystallization and the ultimate device performance.

Efficiency limitations in a low band-gap diketopyrrolopyrrole-based polymer solar cell.

We report the performance and photophysics of a low band-gap diketopyrrolopyrrole-based copolymer used in bulk heterojunction devices in combination with PC71BM. We show that the short lifetime of photogenerated excitons in the polymer constitutes an obstacle towards device efficiency by limiting the diffusion range of the exciton to the donor-acceptor heterojunction. We employ ultrafast transient-probe and fluorescence spectroscopy techniques to examine the excited state loss channels inside the devices. We use the high boiling point solvent additive 1,8-diiodooctane (DIO) to study the photoexcited state losses in different blend morphologies. The solvent additive acts as a compatibiliser between the donor and the acceptor material and leads to smaller domain sizes, higher charge formation yields and increased device efficiency.

High Photoluminescence Efficiency and Optically Pumped Lasing in Solution-Processed Mixed Halide Perovskite Semiconductors.

The study of the photophysical properties of organic-metallic lead halide perovskites, which demonstrate excellent photovoltaic performance in devices with electron- and hole-accepting layers, helps to understand their charge photogeneration and recombination mechanism and unravels their potential for other optoelectronic applications. We report surprisingly high photoluminescence (PL) quantum efficiencies, up to 70%, in these solution-processed crystalline films. We find that photoexcitation in the pristine CH3NH3PbI3-xClx perovskite results in free charge carrier formation within 1 ps and that these free charge carriers undergo bimolecular recombination on time scales of 10s to 100s of ns. To exemplify the high luminescence yield of the CH3NH3PbI3-xClx perovskite, we construct and demonstrate the operation of an optically pumped vertical cavity laser comprising a layer of perovskite between a dielectric mirror and evaporated gold top mirrors. These long carrier lifetimes together with exceptionally high luminescence yield are unprecedented in such simply prepared inorganic semiconductors, and we note that these properties are ideally suited for photovoltaic diode operation.

Enhanced nanoscale imaging of polymer blends by temperature-controlled selective dissolution.

Nanoscale imaging on polymer blends is vital, especially in organic electronics. By using temperature-controlled selective dissolution, the 3D structure of a thin film becomes accessible without the expensive search for adequate orthogonal solvents. The method, which takes advantage of the temperature dependence of the solubility, is demonstrated to image P3HT:PCBM and P3HT:F8TBT photovoltaic blend films using atomic force and scanning electron microscopy.

Dye-sensitized solar cell based on a three-dimensional photonic crystal.

We present a material assembly route for the manufacture of dye-sensitized solar cells, coupling a high-surface mesoporous layer to a three-dimensional photonic crystal (PC). Material synthesis aided by self-assembly on two length scales provided electrical and pore connectivity at the mesoporous and the microporous level. This construct allows effective dye sensitization, electrolyte infiltration, and charge collection from both the mesoporous and the PC layers, opening up additional parameter space for effective light management by harvesting PC-induced resonances.

Formation of nanopatterned polymer blends in photovoltaic devices.

In this paper, we demonstrate a double nanoimprinting process that allows the formation of nanostructured polymer heterojunctions of composition and morphology that can be selected independently. We fabricated photovoltaic (PV) devices with extremely high densities (10(14)/mm(2)) of interpenetrating nanoscale columnar features in the active polymer blend layer. The smallest feature sizes are as small as 25 nm on a 50 nm pitch, which results in a spacing of heterojunctions at or below the exciton diffusion length. Photovoltaic devices based on double-imprinted poly((9,9-dioctylfluorene)-2,7-diyl-alt-[4,7-bis(3-hexylthien-5-yl)-2,1,3-benzothiadiazole]-2',2''-diyl) (F8TBT)/ poly(3-hexylthiophene) (P3HT) films are among the best polymer-polymer blend devices reported to date with a power conversion efficiency (PCE, eta(e)) of 1.9%.