Technology Platform for Sampling Water with Electrolyte-Gated Organic Transistors Sensitised with Langmuiur-Deposited Calixarene Surface Layers.

We demonstrate a technology platform that enables the development of new, surface-sensitised organic transistor sensors. We show that an organic semiconductor can still be gated by an electric double layer within the electrochemical window of water after the deposition of up to four Langmuir- Schäfer calixarene layers onto its surface. Since many calixarenes are known to selectively bind waterborne cations, this facilitates sensitising a conventional organic semiconductor with a physically deposited layer for specific cation recognition. When at least two Langmuir-Schäfer layers are deposited, these also block the electrochemical doping of the organic semiconductor, which otherwise competes with the field effect in water-gated organic transistors. Carrier mobility is reduced by the application of calixarene layers, but transistor current measurement remains accessible by simple methods. We find that for the present purpose, Langmuir-Schäfer-printed surface layers perform better than those deposited by Langmuir-Blodgett deposition

Innate cation sensitivity in a semiconducting polymer

Water- gated organic thin film transistors (OTFTs) using the hole transporting semiconducting polymer, poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT), show an innate response of their threshold voltage to the addition of divalent metal cations to the gating water, without deliberately introducing an ion- sensitive component. A similar threshold response is shown for several divalent cations, but is absent for monovalent cations. Response is absent for transistors using the inorganic semiconductor ZnO, or the similar organic semiconductor poly(3-hexylthiophene) (rrP3HT), instead of PBTTT. We assign innate cation sensitivity to residues of the organometallic Pd(0) complex used as catalyst in PBTTT synthesis which bears strong resemblance to typical metal chelating agents. Organometallic Pd(0) residues are absent from ZnO, and also from rrP3HT which is polymerised with a different type of catalyst. However, when Pd(0) complex is deliberately added to rrP3HT casting solutions, resulting OTFTs also display threshold response to a divalent cation

Sub-nanomolar detection of Cesium with water-gated transistor

Caesium (Cs + ) cations are rare in nature but the β - active radioisotope 137 Cs can be released in nuclear incidents and find its way into the water supply, where it is harmful to humans and animals drinking it. We here report a water-gated thin film transistor (WGTFT) which allows the detection of Cs + in drinking water at very low concentrations. The transistor channel is formed from spray pyrolysed tin dioxide, SnO 2 which gives WGTFTs with near- zero initial threshold. When the WGTFT is sensitised with a plasticised PVC membrane containing the Cs + - selective zeolite ‘mordenite’, it displays a threshold shift when exposed to drinking water samples carrying traces of Cs + . The response characteristic is given by the Langmuir adsorption isotherm instead of the NikolskyEisenman law commonly found for ion- sensitive WGTFTs sensitised with organic ionophores. We find a complex stability constant K = (3.9 +/- 0.4) x 10 9 L / mole and a limit-of detection (LoD) of 33 pM. Our LoD is far lower than the Cs + potability limit of 7.5 nM, which cannot be met by organicsensitised membranes where LoD is typically in the order of 100 nM or more

A water-gated organic thin film transistor as a sensor for water-borne amines

The p-type semiconducting polymer Poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT) displays innate sensitivity to water-borne amines. We demonstrate this with the help of water- gated PBTTT thin film transistors (TFTs). When octylamine is added to the gating water, TFTs respond with a significantly reduced saturated drain current. Underlying TFT drift is minimised by initial conditioning, and remaining drift can be accounted for by normalising current response to the current level under purge immediately before exposure. Normalised current response vs. amine concentration is reproducible between different transistors, and can be modelled by a Langmuir surface adsorption isotherm, which suggests physisorption of analyte at the PBTTT surface, rather than bulk penetration. Same PBTTT transistors do not respond to 1- octanol, confirming the specific affinity between amines and thiophene- based organic semiconductors

National, clinical cohort study of late effects among survivors of acute lymphoblastic leukaemia:The ALL-STAR study protocol

Introduction More than 90% of patients diagnosed with childhood acute lymphoblastic leukaemia (ALL) today will survive. However, half of the survivors are expected to experience therapy-related chronic or late occurring adverse effects, reducing quality of life. Insight into underlying risk trajectories is warranted. The aim of this study is to establish a Nordic, national childhood ALL survivor cohort, to be investigated for the total somatic and psychosocial treatment-related burden as well as associated risk factors, allowing subsequent linkage to nation-wide public health registers.Methods and analysis This population-based observational cohort study includes clinical follow-up of a retrospective childhood ALL survivor cohort (n=475), treated according to a common Nordic ALL protocol during 2008–2018 in Denmark. The study includes matched controls. Primary endpoints are the cumulative incidence and cumulative burden of 197 health conditions, assessed through self-report and proxy-report questionnaires, medical chart validation, and clinical examinations. Secondary endpoints include organ-specific outcome, including cardiovascular and pulmonary function, physical performance, neuropathy, metabolic disturbances, hepatic and pancreatic function, bone health, oral and dental health, kidney function, puberty and fertility, fatigue, and psychosocial outcome. Therapy exposure, acute toxicities, and host genome variants are explored as risk factors.Ethics and dissemination The study is approved by the Regional Ethics Committee for the Capital Region in Denmark (H-18035090/H-20006359) and by the Danish Data Protection Agency (VD-2018–519). Results will be published in peer-reviewed journals and are expected to guide interventions that will ameliorate the burden of therapy without compromising the chance of cure

Fibre optic absorbance meter with low limit of detection for waterborne cations

We report an evanescent wave based fibre optic absorbance meter that enables the colorimetric detection of waterborne cations with water insoluble chromoionophoric sensitisers. This establishes an alternative to the PVC membrane based transducers that are conventionally used for this purpose. Here, a water insoluble sensitiser is coated as a thin film on an unclad section of a multimode optical fibre to overlap with the evanescent field of a light beam propagating along the fibre core. The colorimetric response of the sensitiser when in contact with waterborne cation leads to increased absorption of virtual photons associated with the evanescent field. The resulting intensity loss of the propagating beam is detected by a bespoke newly designed self- referenced evanescent wave absorbance meter with beam intensity modulation and Lock-in amplification. We validate our transducer with the well characterised water insoluble sensitizer, 1-(2-pyridylazo)-2-naphthol (PAN), for the detection of aqueous Zn2+ cations. We find a limit of detection (LoD) of 54 nM Zn2+, 28 times lower compared to a PVC membrane based sensor using same sensitiser for same cation (Albero et al., Journal of Pharmaceutical and Biomedical Analysis 29 (2002), 779). Our evanescent wave absorbance meter can easily be adapted to other colorimetric sensitisers, including chromoionophoric complex forming macrocycles

FAN, a Novel WD-Repeat Protein, Couples the p55 TNF-Receptor to Neutral Sphingomyelinase

AbstractThe initiation of intracellular signaling events through the 55 kDa tumor necrosis factor–receptor (TNF-R55) appears to depend on protein intermediates that interact with specific cytoplasmic domains of TNF-R55. By combined use of the yeast interaction trap system and a peptide scanning library, the novel WD-repeat protein FAN has been identified, which specifically binds to a cytoplasmic nine amino acid binding motif of TNF-R55. This region has been previously recognized as a distinct functional domain that is both required and sufficient for the activation of neutral sphingomyelinase (N-SMase). Overexpression of full-length FAN enhanced N-SMase activity in TNF–treated cells, while truncated mutants of FAN produced dominant negative effects. The data suggest that FAN regulates ceramide production by N-SMase, which is a crucial step in TNF signaling

Tuning intermolecular interactions in di-octyl substituted polyfluorene via hydrostatic pressure

Polyfluorenes (PFs) represent a unique class of poly para-phenylene based blue-emitting polymers with intriguing structure-property relationships. Slight variations in the choice of functionalizing side chains result in dramatic differences in the inter- and intra-chain structures in PFs. We present photoluminescence (PL) and Raman scattering studies of bulk samples and thin films of dioctyl-substituted PF (PF8) under hydrostatic pressure. The bulk sample was further thermally annealed at 1.9 GPa. The PL vibronics of the as-is sample red-shift at an average rate of 26 meV/GPa. The thermally annealed sample is characterized by at least two phase transitions at 1.1 GPa and 4.2 GPa, each of which has a different pressure coefficient for PL vibronics. The Huang-Rhys factor, a measure of the electron-phonon interaction, is found to increase with increasing pressures signaling a higher geometric relaxation of the electronic states. The Raman peaks harden with increasing pressures; the intra-ring C-C stretch frequency at 1600 cm$^{-1}$ has a pressure coefficient of 7.2 cm$^{-1}$/GPa and exhibits asymmetric line shapes at higher pressures, characteristic of a strong electron-phonon interaction. The optical properties of PF8 under high pressure are further contrasted with those of a branched side chain substituted PF.Comment: 22 pages, 10 figure

Largeâ eddy simulation of biogenic VOC chemistry during the DISCOVERâ AQ 2011 campaign

Biogenic volatile organic compounds (BVOCs) are oxidized quickly in the atmosphere to form oxygenated VOC (OVOC) and play crucial roles in the formation of ozone and secondary organic aerosols. We use the National Center for Atmospheric Research’s largeâ eddy simulation model and Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality 2011 flight data to understand the role of boundary layer turbulence on the atmospheric chemistry of key BVOC species and their oxidation products. We simulate three distinct convective environments during the campaign, representing fair weather conditions (case 1: 1 July), a convective event dominated by southwesterly flow (case 2: 11 July), and a polluted event with high temperature and convection (case 3: 29 July). Isoprene segregation is greatest in the lower boundary layer under warm and convective conditions, reaching up to a 10% reduction in the isopreneâ OH reaction rate. Under warm and convective conditions, the BVOC lifetimes lengthen due to increased isoprene emission, elevated initial chemical concentrations, and OH competition. Although turbulenceâ driven segregation has less influence on the OVOC species, convection mixes more OVOC into the upper atmospheric boundary layer (ABL) and increases the total OH reactivity. Production and loss rates of ozone above 2â km in all the three cases indicate in situ ozone formation in addition to vertical convective transport of ozone from the surface and aloft, consistent with the increased contribution of OH reactivity from OVOC. Together, these results show that total OH reactivity in the ABL increases under warmer and stronger convective conditions due to enhanced isoprene emission and the OVOC contribution to ozone formation.Key PointsLES and DISCOVERâ AQ flight data are compared to understand the role of turbulence on BVOC chemistryTurbulenceâ induced segregation is less important for OVOC than isoprene, but OVOC compensates for isoprene rate reductionsConvection mixes more OVOC into the upper ABL and increases total OH reactivityPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/133566/1/jgrd53113_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/133566/2/jgrd53113-sup-0001-SI-S01.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/133566/3/jgrd53113.pd